Add BUILD.gn, clean up code, and made minor changes

Changes described in README.fuchsia

Change-Id: Idd810e11e7a07f4a1f8049e4914c0227f9b1d7d5
diff --git a/ANNOUNCE b/ANNOUNCE
deleted file mode 100644
index bca4250..0000000
--- a/ANNOUNCE
+++ /dev/null
@@ -1,88 +0,0 @@
-Libpng 1.6.24 - August 4, 2016
-
-This is a public release of libpng, intended for use in production codes.
-
-Files available for download:
-
-Source files with LF line endings (for Unix/Linux) and with a
-"configure" script
-
-   libpng-1.6.24.tar.xz (LZMA-compressed, recommended)
-   libpng-1.6.24.tar.gz
-
-Source files with CRLF line endings (for Windows), without the
-"configure" script
-
-   lpng1624.7z  (LZMA-compressed, recommended)
-   lpng1624.zip
-
-Other information:
-
-   libpng-1.6.24-README.txt
-   libpng-1.6.24-LICENSE.txt
-   libpng-1.6.24-*.asc (armored detached GPG signatures)
-
-Changes since the last public release (1.6.23):
-  Avoid potential overflow of the PNG_IMAGE_SIZE macro.  This macro
-    is not used within libpng, but is used in some of the examples.
-  Correct filter heuristic overflow handling. This was broken when the
-    write filter code was moved out-of-line; if there is a single filter and
-    the heuristic sum overflows the calculation of the filtered line is not
-    completed.  In versions prior to 1.6 the code was duplicated in-line
-    and the check not performed, so the filter operation completed; however,
-    in the multi-filter case where the sum is performed the 'none' filter would
-    be selected if all the sums overflowed, even if it wasn't in the filter
-    list.  The fix to the first problem is simply to provide PNG_SIZE_MAX as
-    the current lmins sum value; this means the sum can never exceed it and
-    overflows silently.  A reasonable compiler that does choose to inline
-    the code will simply eliminate the sum check.
-  The fix to the second problem is to use high precision arithmetic (this is
-    implemented in 1.7), however a simple safe fix here is to chose the lowest
-    numbered filter in the list from png_set_filter (this only works if the
-    first problem is also fixed) (John Bowler).
-  Use a more efficient absolute value calculation on SSE2 (Matthieu Darbois).
-  Fixed the case where PNG_IMAGE_BUFFER_SIZE can overflow in the application
-    as a result of the application using an increased 'row_stride'; previously
-    png_image_finish_read only checked for overflow on the base calculation of
-    components.  (I.e. it checked for overflow of a 32-bit number on the total
-    number of pixel components in the output format, not the possibly padded row
-    length and not the number of bytes, which for linear formats is twice the
-    number of components.)
-  MSVC does not like '-(unsigned)', so replaced it with 0U-(unsigned)
-  MSVC does not like (uInt) = -(unsigned) (i.e. as an initializer), unless
-    the conversion is explicitly invoked by a cast.
-  Put the SKIP definition in the correct place. It needs to come after the
-    png.h include (see all the other .c files in contrib/libtests) because it
-    depends on PNG_LIBPNG_VER.
-  Removed the three compile warning options from the individual project
-    files into the zlib.props globals.  It increases the warning level from 4
-    to All and adds a list of the warnings that need to be turned off.  This is
-    semi-documentary; the intent is to tell libpng users which warnings have
-    been examined and judged non-fixable at present.  The warning about
-    structure padding is fixable, but it would be a signficant change (moving
-    structure members around).
-  Optimized absolute value calculation in filter selection, similar to
-    code in the PAETH decoder in pngrutil.c. Build with PNG_USE_ABS to
-    use this.
-  Added pngcp to the build together with a pngcp.dfa configuration test.
-  Added high resolution timing to pngcp.
-  Added "Common linking failures" section to INSTALL.
-  Relocated misplaced #endif in png.c sRGB profile checking.
-  Fixed two Coverity issues in pngcp.c.
-  Avoid filter-selection heuristic sum calculations in cases where only one
-    filter is a candidate for selection. This trades off code size (added
-    private png_setup_*_row_only() functions) for speed.
-  Fixed some indentation to comply with our coding style.
-  Added contrib/tools/reindent.
-  Eliminated unnecessary tests of boolean png_isaligned() vs 0.
-  Conditionally compile SSE2 headers in contrib/intel/intel_sse.patch
-  Conditionally compile png_decompress_chunk().
-  Conditionally compile ARM_NEON headers in pngpriv.h
-  Updated contrib/intel/intel_sse.patch
-
-(subscription required; visit
-https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe)
-or to glennrp at users.sourceforge.net
-
-Glenn R-P
diff --git a/BUILD.gn b/BUILD.gn
new file mode 100644
index 0000000..bbc1089
--- /dev/null
+++ b/BUILD.gn
@@ -0,0 +1,73 @@
+# Copyright 2016 The Fuchsia Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/arm.gni")
+
+config("libpng_config") {
+  include_dirs = [ "." ]
+  defines = []
+}
+# Must be in a config because of how GN orders flags (otherwise -Wall will
+# appear after this, and turn it back on).
+config("clang_warnings") {
+  if (is_clang) {
+    cflags = [
+      # libpng checks that the width is not greater than PNG_SIZE_MAX.
+      # On platforms where size_t is 64-bits, this comparison will always
+      # be false.
+      "-Wno-tautological-constant-out-of-range-compare",
+    ]
+  }
+}
+
+source_set("libpng") {
+  sources = [
+    "png.c",
+    "png.h",
+    "pngconf.h",
+    "pngerror.c",
+    "pngget.c",
+    "pnginfo.h",
+    "pnglibconf.h",
+    "pngmem.c",
+    "pngpread.c",
+    "pngprefix.h",
+    "pngpriv.h",
+    "pngread.c",
+    "pngrio.c",
+    "pngrtran.c",
+    "pngrutil.c",
+    "pngset.c",
+    "pngstruct.h",
+    "pngtrans.c",
+    "pngwio.c",
+    "pngwrite.c",
+    "pngwtran.c",
+    "pngwutil.c",
+  ]
+  defines = []
+  cflags = []
+  if (current_cpu == "x86" || current_cpu == "x64") {
+    sources += [
+      "contrib/intel/filter_sse2_intrinsics.c",
+      "contrib/intel/intel_init.c",
+    ]
+    defines += [ "PNG_INTEL_SSE_OPT=1" ]
+  } else if ((current_cpu == "arm" || current_cpu == "arm64") && arm_use_neon) {
+    sources += [
+      "arm/arm_init.c",
+      "arm/filter_neon_intrinsics.c",
+    ]
+    defines += [
+      "PNG_ARM_NEON_OPT=2",
+      "PNG_ARM_NEON_IMPLEMENTATION=1",
+    ]
+  }
+
+  public_configs = [ ":libpng_config" ]
+  public_deps = [
+    "//third_party/zlib",
+  ]
+  configs += [ ":clang_warnings" ]
+}
diff --git a/CHANGES b/CHANGES
deleted file mode 100644
index d4f0c8b..0000000
--- a/CHANGES
+++ /dev/null
@@ -1,5685 +0,0 @@
-#if 0
-CHANGES - changes for libpng
-
-version 0.1 [March 29, 1995]
-  initial work-in-progress release
-
-version 0.2 [April 1, 1995]
-  added reader into png.h
-  fixed small problems in stub file
-
-version 0.3 [April 8, 1995]
-  added pull reader
-  split up pngwrite.c to several files
-  added pnglib.txt
-  added example.c
-  cleaned up writer, adding a few new transformations
-  fixed some bugs in writer
-  interfaced with zlib 0.5
-  added K&R support
-  added check for 64 KB blocks for 16 bit machines
-
-version 0.4 [April 26, 1995]
-  cleaned up code and commented code
-  simplified time handling into png_time
-  created png_color_16 and png_color_8 to handle color needs
-  cleaned up color type defines
-  fixed various bugs
-  made various names more consistent
-  interfaced with zlib 0.71
-  cleaned up zTXt reader and writer (using zlib's Reset functions)
-  split transformations into pngrtran.c and pngwtran.c
-
-version 0.5 [April 30, 1995]
-  interfaced with zlib 0.8
-  fixed many reading and writing bugs
-  saved using 3 spaces instead of tabs
-
-version 0.6 [May 1, 1995]
-  first beta release
-  added png_large_malloc() and png_large_free()
-  added png_size_t
-  cleaned up some compiler warnings
-  added png_start_read_image()
-
-version 0.7 [June 24, 1995]
-  cleaned up lots of bugs
-  finished dithering and other stuff
-  added test program
-  changed name from pnglib to libpng
-
-version 0.71 [June 26, 1995]
-  changed pngtest.png for zlib 0.93
-  fixed error in libpng.txt and example.c
-
-version 0.8 [August 20, 1995]
-  cleaned up some bugs
-  added png_set_filler()
-  split up pngstub.c into pngmem.c, pngio.c, and pngerror.c
-  added #define's to remove unwanted code
-  moved png_info_init() to png.c
-  added old_size into png_realloc()
-  added functions to manually set filtering and compression info
-  changed compression parameters based on image type
-  optimized filter selection code
-  added version info
-  changed external functions passing floats to doubles (k&r problems?)
-  put all the configurable stuff in pngconf.h
-  enabled png_set_shift to work with paletted images on read
-  added png_read_update_info() - updates info structure with transformations
-
-Version 0.81 [August, 1995]
-  incorporated Tim Wegner's medium model code (thanks, Tim)
-
-Version 0.82 [September, 1995]
-  [unspecified changes]
-
-Version 0.85 [December, 1995]
-  added more medium model code (almost everything's a far)
-  added i/o, error, and memory callback functions
-  fixed some bugs (16-bit, 4-bit interlaced, etc.)
-  added first run progressive reader (barely tested)
-
-Version 0.86 [January, 1996]
-  fixed bugs
-  improved documentation
-
-Version 0.87 [January, 1996]
-  fixed medium model bugs
-  fixed other bugs introduced in 0.85 and 0.86
-  added some minor documentation
-
-Version 0.88 [January, 1996]
-  fixed progressive bugs
-  replaced tabs with spaces
-  cleaned up documentation
-  added callbacks for read/write and warning/error functions
-
-Version 0.89 [June 5, 1996]
-  Added new initialization API to make libpng work better with shared libs
-    we now have png_create_read_struct(), png_create_write_struct(),
-    png_create_info_struct(), png_destroy_read_struct(), and
-    png_destroy_write_struct() instead of the separate calls to
-    malloc and png_read_init(), png_info_init(), and png_write_init()
-  Changed warning/error callback functions to fix bug - this means you
-    should use the new initialization API if you were using the old
-    png_set_message_fn() calls, and that the old API no longer exists
-    so that people are aware that they need to change their code
-  Changed filter selection API to allow selection of multiple filters
-    since it didn't work in previous versions of libpng anyways
-  Optimized filter selection code
-  Fixed png_set_background() to allow using an arbitrary RGB color for
-    paletted images
-  Fixed gamma and background correction for paletted images, so
-    png_correct_palette is not needed unless you are correcting an
-    external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
-    in pngconf.h) - if nobody uses this, it may disappear in the future.
-  Fixed bug with Borland 64K memory allocation (Alexander Lehmann)
-  Fixed bug in interlace handling (Smarasderagd, I think)
-  Added more error checking for writing and image to reduce invalid files
-  Separated read and write functions so that they won't both be linked
-    into a binary when only reading or writing functionality is used
-  New pngtest image also has interlacing and zTXt
-  Updated documentation to reflect new API
-
-Version 0.89c [June 17, 1996]
-  Bug fixes.
-
-Version 0.90 [January, 1997]
-  Made CRC errors/warnings on critical and ancillary chunks configurable
-  libpng will use the zlib CRC routines by (compile-time) default
-  Changed DOS small/medium model memory support - needs zlib 1.04 (Tim Wegner)
-  Added external C++ wrapper statements to png.h (Gilles Dauphin)
-  Allow PNG file to be read when some or all of file signature has already
-    been read from the beginning of the stream.  ****This affects the size
-    of info_struct and invalidates all programs that use a shared libpng****
-  Fixed png_filler() declarations
-  Fixed? background color conversions
-  Fixed order of error function pointers to match documentation
-  Current chunk name is now available in png_struct to reduce the number
-    of nearly identical error messages (will simplify multi-lingual
-    support when available)
-  Try to get ready for unknown-chunk callback functions:
-    - previously read critical chunks are flagged, so the chunk handling
-      routines can determine if the chunk is in the right place
-    - all chunk handling routines have the same prototypes, so we will
-      be able to handle all chunks via a callback mechanism
-  Try to fix Linux "setjmp" buffer size problems
-  Removed png_large_malloc, png_large_free, and png_realloc functions.
-
-Version 0.95 [March, 1997]
-  Fixed bug in pngwutil.c allocating "up_row" twice and "avg_row" never
-  Fixed bug in PNG file signature compares when start != 0
-  Changed parameter type of png_set_filler(...filler...) from png_byte
-    to png_uint_32
-  Added test for MACOS to ensure that both math.h and fp.h are not #included
-  Added macros for libpng to be compiled as a Windows DLL (Andreas Kupries)
-  Added "packswap" transformation, which changes the endianness of
-    packed-pixel bytes (Kevin Bracey)
-  Added "strip_alpha" transformation, which removes the alpha channel of
-    input images without using it (not necessarily a good idea)
-  Added "swap_alpha" transformation, which puts the alpha channel in front
-    of the color bytes instead of after
-  Removed all implicit variable tests which assume NULL == 0 (I think)
-  Changed several variables to "png_size_t" to show 16/32-bit limitations
-  Added new pCAL chunk read/write support
-  Added experimental filter selection weighting (Greg Roelofs)
-  Removed old png_set_rgbx() and png_set_xrgb() functions that have been
-    obsolete for about 2 years now (use png_set_filler() instead)
-  Added macros to read 16- and 32-bit ints directly from buffer, to be
-    used only on those systems that support it (namely PowerPC and 680x0)
-    With some testing, this may become the default for MACOS/PPC systems.
-  Only calculate CRC on data if we are going to use it
-  Added macros for zTXt compression type PNG_zTXt_COMPRESSION_???
-  Added macros for simple libpng debugging output selectable at compile time
-  Removed PNG_READ_END_MODE in progressive reader (Smarasderagd)
-  More description of info_struct in libpng.txt and png.h
-  More instructions in example.c
-  More chunk types tested in pngtest.c
-  Renamed pngrcb.c to pngset.c, and all png_read_<chunk> functions to be
-    png_set_<chunk>.  We now have corresponding png_get_<chunk>
-    functions in pngget.c to get information in info_ptr.  This isolates
-    the application from the internal organization of png_info_struct
-    (good for shared library implementations).
-
-Version 0.96 [May, 1997]
-  Fixed serious bug with < 8bpp images introduced in 0.95
-  Fixed 256-color transparency bug (Greg Roelofs)
-  Fixed up documentation (Greg Roelofs, Laszlo Nyul)
-  Fixed "error" in pngconf.h for Linux setjmp() behavior
-  Fixed DOS medium model support (Tim Wegner)
-  Fixed png_check_keyword() for case with error in static string text
-  Added read of CRC after IEND chunk for embedded PNGs (Laszlo Nyul)
-  Added typecasts to quiet compiler errors
-  Added more debugging info
-
-Version 0.97 [January, 1998]
-  Removed PNG_USE_OWN_CRC capability
-  Relocated png_set_crc_action from pngrutil.c to pngrtran.c
-  Fixed typecasts of "new_key", etc. (Andreas Dilger)
-  Added RFC 1152 [sic] date support
-  Fixed bug in gamma handling of 4-bit grayscale
-  Added 2-bit grayscale gamma handling (Glenn R-P)
-  Added more typecasts. 65536L becomes (png_uint_32)65536L, etc. (Glenn R-P)
-  Minor corrections in libpng.txt
-  Added simple sRGB support (Glenn R-P)
-  Easier conditional compiling, e.g.,
-    define PNG_READ/WRITE_NOT_FULLY_SUPPORTED;
-    all configurable options can be selected from command-line instead
-    of having to edit pngconf.h (Glenn R-P)
-  Fixed memory leak in pngwrite.c (free info_ptr->text) (Glenn R-P)
-  Added more conditions for png_do_background, to avoid changing
-    black pixels to background when a background is supplied and
-    no pixels are transparent
-  Repaired PNG_NO_STDIO behavior
-  Tested NODIV support and made it default behavior (Greg Roelofs)
-  Added "-m" option and PNGTEST_DEBUG_MEMORY to pngtest (John Bowler)
-  Regularized version numbering scheme and bumped shared-library major
-    version number to 2 to avoid problems with libpng 0.89 apps
-    (Greg Roelofs)
-
-Version 0.98 [January, 1998]
-  Cleaned up some typos in libpng.txt and in code documentation
-  Fixed memory leaks in pCAL chunk processing (Glenn R-P and John Bowler)
-  Cosmetic change "display_gamma" to "screen_gamma" in pngrtran.c
-  Changed recommendation about file_gamma for PC images to .51 from .45,
-    in example.c and libpng.txt, added comments to distinguish between
-    screen_gamma, viewing_gamma, and display_gamma.
-  Changed all references to RFC1152 to read RFC1123 and changed the
-    PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
-  Added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
-  Changed srgb_intent from png_byte to int to avoid compiler bugs
-
-Version 0.99 [January 30, 1998]
-  Free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
-  Fixed a longstanding "packswap" bug in pngtrans.c
-  Fixed some inconsistencies in pngconf.h that prevented compiling with
-    PNG_READ_GAMMA_SUPPORTED and PNG_READ_hIST_SUPPORTED undefined
-  Fixed some typos and made other minor rearrangement of libpng.txt (Andreas)
-  Changed recommendation about file_gamma for PC images to .50 from .51 in
-    example.c and libpng.txt, and changed file_gamma for sRGB images to .45
-  Added a number of functions to access information from the png structure
-    png_get_image_height(), etc. (Glenn R-P, suggestion by Brad Pettit)
-  Added TARGET_MACOS similar to zlib-1.0.8
-  Define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
-  Added type casting to all png_malloc() function calls
-
-Version 0.99a [January 31, 1998]
-  Added type casts and parentheses to all returns that return a value.(Tim W.)
-
-Version 0.99b [February 4, 1998]
-  Added type cast png_uint_32 on malloc function calls where needed.
-  Changed type of num_hist from png_uint_32 to int (same as num_palette).
-  Added checks for rowbytes overflow, in case png_size_t is less than 32 bits.
-  Renamed makefile.elf to makefile.lnx.
-
-Version 0.99c [February 7, 1998]
-  More type casting.  Removed erroneous overflow test in pngmem.c.
-  Added png_buffered_memcpy() and png_buffered_memset(), apply them to rowbytes.
-  Added UNIX manual pages libpng.3 (incorporating libpng.txt) and  png.5.
-
-Version 0.99d [February 11, 1998]
-  Renamed "far_to_near()" "png_far_to_near()"
-  Revised libpng.3
-  Version 99c "buffered" operations didn't work as intended.  Replaced them
-    with png_memcpy_check() and png_memset_check().
-  Added many "if (png_ptr == NULL) return" to quell compiler warnings about
-    unused png_ptr, mostly in pngget.c and pngset.c.
-  Check for overlength tRNS chunk present when indexed-color PLTE is read.
-  Cleaned up spelling errors in libpng.3/libpng.txt
-  Corrected a problem with png_get_tRNS() which returned undefined trans array
-
-Version 0.99e [February 28, 1998]
-  Corrected png_get_tRNS() again.
-  Add parentheses for easier reading of pngget.c, fixed "||" should be "&&".
-  Touched up example.c to make more of it compileable, although the entire
-    file still can't be compiled (Willem van Schaik)
-  Fixed a bug in png_do_shift() (Bryan Tsai)
-  Added a space in png.h prototype for png_write_chunk_start()
-  Replaced pngtest.png with one created with zlib 1.1.1
-  Changed pngtest to report PASS even when file size is different (Jean-loup G.)
-  Corrected some logic errors in png_do_invert_alpha() (Chris Patterson)
-
-Version 0.99f [March 5, 1998]
-  Corrected a bug in pngpread() introduced in version 99c (Kevin Bracey)
-  Moved makefiles into a "scripts" directory, and added INSTALL instruction file
-  Added makefile.os2 and pngos2.def (A. Zabolotny) and makefile.s2x (W. Sebok)
-  Added pointers to "note on libpng versions" in makefile.lnx and README
-  Added row callback feature when reading and writing nonprogressive rows
-    and added a test of this feature in pngtest.c
-  Added user transform callbacks, with test of the feature in pngtest.c
-
-Version 0.99g [March 6, 1998, morning]
-  Minor changes to pngtest.c to suppress compiler warnings.
-  Removed "beta" language from documentation.
-
-Version 0.99h [March 6, 1998, evening]
-  Minor changes to previous minor changes to pngtest.c
-  Changed PNG_READ_NOT_FULLY_SUPPORTED to PNG_READ_TRANSFORMS_NOT_SUPPORTED
-    and added PNG_PROGRESSIVE_READ_NOT_SUPPORTED macro
-  Added user transform capability
-
-Version 1.00 [March 7, 1998]
-  Changed several typedefs in pngrutil.c
-  Added makefile.wat (Pawel Mrochen), updated makefile.tc3 (Willem van Schaik)
-  Replaced "while(1)" with "for(;;)"
-  Added PNGARG() to prototypes in pngtest.c and removed some prototypes
-  Updated some of the makefiles (Tom Lane)
-  Changed some typedefs (s_start, etc.) in pngrutil.c
-  Fixed dimensions of "short_months" array in pngwrite.c
-  Replaced ansi2knr.c with the one from jpeg-v6
-
-Version 1.0.0 [March 8, 1998]
-  Changed name from 1.00 to 1.0.0 (Adam Costello)
-  Added smakefile.ppc (with SCOPTIONS.ppc) for Amiga PPC (Andreas Kleinert)
-
-Version 1.0.0a [March 9, 1998]
-  Fixed three bugs in pngrtran.c to make gamma+background handling consistent
-    (Greg Roelofs)
-  Changed format of the PNG_LIBPNG_VER integer to xyyzz instead of xyz
-    for major, minor, and bugfix releases.  This is 10001. (Adam Costello,
-    Tom Lane)
-  Make months range from 1-12 in png_convert_to_rfc1123
-
-Version 1.0.0b [March 13, 1998]
-  Quieted compiler complaints about two empty "for" loops in pngrutil.c
-  Minor changes to makefile.s2x
-  Removed #ifdef/#endif around a png_free() in pngread.c
-
-Version 1.0.1 [March 14, 1998]
-  Changed makefile.s2x to reduce security risk of using a relative pathname
-  Fixed some typos in the documentation (Greg).
-  Fixed a problem with value of "channels" returned by png_read_update_info()
-
-Version 1.0.1a [April 21, 1998]
-  Optimized Paeth calculations by replacing abs() function calls with intrinsics
-  plus other loop optimizations. Improves avg decoding speed by about 20%.
-  Commented out i386istic "align" compiler flags in makefile.lnx.
-  Reduced the default warning level in some makefiles, to make them consistent.
-  Removed references to IJG and JPEG in the ansi2knr.c copyright statement.
-  Fixed a bug in png_do_strip_filler with XXRRGGBB => RRGGBB transformation.
-  Added grayscale and 16-bit capability to png_do_read_filler().
-  Fixed a bug in pngset.c, introduced in version 0.99c, that sets rowbytes
-    too large when writing an image with bit_depth < 8 (Bob Dellaca).
-  Corrected some bugs in the experimental weighted filtering heuristics.
-  Moved a misplaced pngrutil code block that truncates tRNS if it has more
-    than num_palette entries -- test was done before num_palette was defined.
-  Fixed a png_convert_to_rfc1123() bug that converts day 31 to 0 (Steve Eddins).
-  Changed compiler flags in makefile.wat for better optimization
-    (Pawel Mrochen).
-
-Version 1.0.1b [May 2, 1998]
-  Relocated png_do_gray_to_rgb() within png_do_read_transformations() (Greg).
-  Relocated the png_composite macros from pngrtran.c to png.h (Greg).
-  Added makefile.sco (contributed by Mike Hopkirk).
-  Fixed two bugs (missing definitions of "istop") introduced in libpng-1.0.1a.
-  Fixed a bug in pngrtran.c that would set channels=5 under some circumstances.
-  More work on the Paeth-filtering, achieving imperceptible speedup
-    (A Kleinert).
-  More work on loop optimization which may help when compiled with C++
-    compilers.
-  Added warnings when people try to use transforms they've defined out.
-  Collapsed 4 "i" and "c" loops into single "i" loops in pngrtran and pngwtran.
-  Revised paragraph about png_set_expand() in libpng.txt and libpng.3 (Greg)
-
-Version 1.0.1c [May 11, 1998]
-  Fixed a bug in pngrtran.c (introduced in libpng-1.0.1a) where the masks for
-    filler bytes should have been 0xff instead of 0xf.
-  Added max_pixel_depth=32 in pngrutil.c when using FILLER with palette images.
-  Moved PNG_WRITE_WEIGHTED_FILTER_SUPPORTED and PNG_WRITE_FLUSH_SUPPORTED
-    out of the PNG_WRITE_TRANSFORMS_NOT_SUPPORTED block of pngconf.h
-  Added "PNG_NO_WRITE_TRANSFORMS" etc., as alternatives for *_NOT_SUPPORTED,
-    for consistency, in pngconf.h
-  Added individual "ifndef PNG_NO_[CAPABILITY]" in pngconf.h to make it easier
-    to remove unwanted capabilities via the compile line
-  Made some corrections to grammar (which, it's) in documentation (Greg).
-  Corrected example.c, use of row_pointers in png_write_image().
-
-Version 1.0.1d [May 24, 1998]
-  Corrected several statements that used side effects illegally in pngrutil.c
-    and pngtrans.c, that were introduced in version 1.0.1b
-  Revised png_read_rows() to avoid repeated if-testing for NULL (A Kleinert)
-  More corrections to example.c, use of row_pointers in png_write_image()
-    and png_read_rows().
-  Added pngdll.mak and pngdef.pas to scripts directory, contributed by
-    Bob Dellaca, to make a png32bd.dll with Borland C++ 4.5
-  Fixed error in example.c with png_set_text: num_text is 3, not 2 (Guido V.)
-  Changed several loops from count-down to count-up, for consistency.
-
-Version 1.0.1e [June 6, 1998]
-  Revised libpng.txt and libpng.3 description of png_set_read|write_fn(), and
-    added warnings when people try to set png_read_fn and png_write_fn in
-    the same structure.
-  Added a test such that png_do_gamma will be done when num_trans==0
-    for truecolor images that have defined a background.  This corrects an
-    error that was introduced in libpng-0.90 that can cause gamma processing
-    to be skipped.
-  Added tests in png.h to include "trans" and "trans_values" in structures
-    when PNG_READ_BACKGROUND_SUPPORTED or PNG_READ_EXPAND_SUPPORTED is defined.
-  Add png_free(png_ptr->time_buffer) in png_destroy_read_struct()
-  Moved png_convert_to_rfc_1123() from pngwrite.c to png.c
-  Added capability for user-provided malloc_fn() and free_fn() functions,
-    and revised pngtest.c to demonstrate their use, replacing the
-    PNGTEST_DEBUG_MEM feature.
-  Added makefile.w32, for Microsoft C++ 4.0 and later (Tim Wegner).
-
-Version 1.0.2 [June 14, 1998]
-  Fixed two bugs in makefile.bor .
-
-Version 1.0.2a [December 30, 1998]
-  Replaced and extended code that was removed from png_set_filler() in 1.0.1a.
-  Fixed a bug in png_do_filler() that made it fail to write filler bytes in
-    the left-most pixel of each row (Kevin Bracey).
-  Changed "static pngcharp tIME_string" to "static char tIME_string[30]"
-    in pngtest.c (Duncan Simpson).
-  Fixed a bug in pngtest.c that caused pngtest to try to write a tIME chunk
-    even when no tIME chunk was present in the source file.
-  Fixed a problem in pngrutil.c: gray_to_rgb didn't always work with 16-bit.
-  Fixed a problem in png_read_push_finish_row(), which would not skip some
-    passes that it should skip, for images that are less than 3 pixels high.
-  Interchanged the order of calls to png_do_swap() and png_do_shift()
-    in pngwtran.c (John Cromer).
-  Added #ifdef PNG_DEBUG/#endif surrounding use of PNG_DEBUG in png.h .
-  Changed "bad adaptive filter type" from error to warning in pngrutil.c .
-  Fixed a documentation error about default filtering with 8-bit indexed-color.
-  Separated the PNG_NO_STDIO macro into PNG_NO_STDIO and PNG_NO_CONSOLE_IO
-    (L. Peter Deutsch).
-  Added png_set_rgb_to_gray() and png_get_rgb_to_gray_status() functions.
-  Added png_get_copyright() and png_get_header_version() functions.
-  Revised comments on png_set_progressive_read_fn() in libpng.txt and example.c
-  Added information about debugging in libpng.txt and libpng.3 .
-  Changed "ln -sf" to "ln -s -f" in makefile.s2x, makefile.lnx, and
-    makefile.sco.
-  Removed lines after Dynamic Dependencies" in makefile.aco .
-  Revised makefile.dec to make a shared library (Jeremie Petit).
-  Removed trailing blanks from all files.
-
-Version 1.0.2a [January 6, 1999]
-  Removed misplaced #endif and #ifdef PNG_NO_EXTERN near the end of png.h
-  Added "if" tests to silence complaints about unused png_ptr in png.h and png.c
-  Changed "check_if_png" function in example.c to return true (nonzero) if PNG.
-  Changed libpng.txt to demonstrate png_sig_cmp() instead of png_check_sig()
-    which is obsolete.
-
-Version 1.0.3 [January 14, 1999]
-  Added makefile.hux, for Hewlett Packard HPUX 10.20 and 11.00 (Jim Rice)
-  Added a statement of Y2K compliance in png.h, libpng.3, and Y2KINFO.
-
-Version 1.0.3a [August 12, 1999]
-  Added check for PNG_READ_INTERLACE_SUPPORTED in pngread.c; issue a warning
-    if an attempt is made to read an interlaced image when it's not supported.
-  Added check if png_ptr->trans is defined before freeing it in pngread.c
-  Modified the Y2K statement to include versions back to version 0.71
-  Fixed a bug in the check for valid IHDR bit_depth/color_types in pngrutil.c
-  Modified makefile.wat (added -zp8 flag, ".symbolic", changed some comments)
-  Replaced leading blanks with tab characters in makefile.hux
-  Changed "dworkin.wustl.edu" to "ccrc.wustl.edu" in various documents.
-  Changed (float)red and (float)green to (double)red, (double)green
-    in png_set_rgb_to_gray() to avoid "promotion" problems in AIX.
-  Fixed a bug in pngconf.h that omitted <stdio.h> when PNG_DEBUG==0 (K Bracey).
-  Reformatted libpng.3 and libpngpf.3 with proper fonts (script by J. vanZandt).
-  Updated documentation to refer to the PNG-1.2 specification.
-  Removed ansi2knr.c and left pointers to the latest source for ansi2knr.c
-    in makefile.knr, INSTALL, and README (L. Peter Deutsch)
-  Fixed bugs in calculation of the length of rowbytes when adding alpha
-    channels to 16-bit images, in pngrtran.c (Chris Nokleberg)
-  Added function png_set_user_transform_info() to store user_transform_ptr,
-    user_depth, and user_channels into the png_struct, and a function
-    png_get_user_transform_ptr() to retrieve the pointer (Chris Nokleberg)
-  Added function png_set_empty_plte_permitted() to make libpng useable
-    in MNG applications.
-  Corrected the typedef for png_free_ptr in png.h (Jesse Jones).
-  Correct gamma with srgb is 45455 instead of 45000 in pngrutil.c, to be
-    consistent with PNG-1.2, and allow variance of 500 before complaining.
-  Added assembler code contributed by Intel in file pngvcrd.c and modified
-    makefile.w32 to use it (Nirav Chhatrapati, INTEL Corporation,
-    Gilles Vollant)
-  Changed "ln -s -f" to "ln -f -s" in the makefiles to make Solaris happy.
-  Added some aliases for png_set_expand() in pngrtran.c, namely
-    png_set_expand_PLTE(), png_set_expand_depth(), and png_set_expand_tRNS()
-    (Greg Roelofs, in "PNG: The Definitive Guide").
-  Added makefile.beo for BEOS on X86, contributed by Sander Stok.
-
-Version 1.0.3b [August 26, 1999]
-  Replaced 2147483647L several places with PNG_MAX_UINT macro, defined in png.h
-  Changed leading blanks to tabs in all makefiles.
-  Define PNG_USE_PNGVCRD in makefile.w32, to get MMX assembler code.
-  Made alternate versions of  png_set_expand() in pngrtran.c, namely
-    png_set_gray_1_2_4_to_8, png_set_palette_to_rgb, and png_set_tRNS_to_alpha
-    (Greg Roelofs, in "PNG: The Definitive Guide").  Deleted the 1.0.3a aliases.
-  Relocated start of 'extern "C"' block in png.h so it doesn't include pngconf.h
-  Revised calculation of num_blocks in pngmem.c to avoid a potentially
-    negative shift distance, whose results are undefined in the C language.
-  Added a check in pngset.c to prevent writing multiple tIME chunks.
-  Added a check in pngwrite.c to detect invalid small window_bits sizes.
-
-Version 1.0.3d [September 4, 1999]
-  Fixed type casting of igamma in pngrutil.c
-  Added new png_expand functions to scripts/pngdef.pas and pngos2.def
-  Added a demo read_user_transform_fn that examines the row filters in pngtest.c
-
-Version 1.0.4 [September 24, 1999, not distributed publicly]
-  Define PNG_ALWAYS_EXTERN in pngconf.h if __STDC__ is defined
-  Delete #define PNG_INTERNAL and include "png.h" from pngasmrd.h
-  Made several minor corrections to pngtest.c
-  Renamed the makefiles with longer but more user friendly extensions.
-  Copied the PNG copyright and license to a separate LICENSE file.
-  Revised documentation, png.h, and example.c to remove reference to
-    "viewing_gamma" which no longer appears in the PNG specification.
-  Revised pngvcrd.c to use MMX code for interlacing only on the final pass.
-  Updated pngvcrd.c to use the faster C filter algorithms from libpng-1.0.1a
-  Split makefile.win32vc into two versions, makefile.vcawin32 (uses MMX
-    assembler code) and makefile.vcwin32 (doesn't).
-  Added a CPU timing report to pngtest.c (enabled by defining PNGTEST_TIMING)
-  Added a copy of pngnow.png to the distribution.
-
-Version 1.0.4a [September 25, 1999]
-  Increase max_pixel_depth in pngrutil.c if a user transform needs it.
-  Changed several division operations to right-shifts in pngvcrd.c
-
-Version 1.0.4b [September 30, 1999]
-  Added parentheses in line 3732 of pngvcrd.c
-  Added a comment in makefile.linux warning about buggy -O3 in pgcc 2.95.1
-
-Version 1.0.4c [October 1, 1999]
-  Added a "png_check_version" function in png.c and pngtest.c that will generate
-    a helpful compiler error if an old png.h is found in the search path.
-  Changed type of png_user_transform_depth|channels from int to png_byte.
-  Added "Libpng is OSI Certified Open Source Software" statement to png.h
-
-Version 1.0.4d [October 6, 1999]
-  Changed 0.45 to 0.45455 in png_set_sRGB()
-  Removed unused PLTE entries from pngnow.png
-  Re-enabled some parts of pngvcrd.c (png_combine_row) that work properly.
-
-Version 1.0.4e [October 10, 1999]
-  Fixed sign error in pngvcrd.c (Greg Roelofs)
-  Replaced some instances of memcpy with simple assignments in pngvcrd (GR-P)
-
-Version 1.0.4f [October 15, 1999]
-  Surrounded example.c code with #if 0 .. #endif to prevent people from
-    inadvertently trying to compile it.
-  Changed png_get_header_version() from a function to a macro in png.h
-  Added type casting mostly in pngrtran.c and pngwtran.c
-  Removed some pointless "ptr = NULL" in pngmem.c
-  Added a "contrib" directory containing the source code from Greg's book.
-
-Version 1.0.5 [October 15, 1999]
-  Minor editing of the INSTALL and README files.
-
-Version 1.0.5a [October 23, 1999]
-  Added contrib/pngsuite and contrib/pngminus (Willem van Schaik)
-  Fixed a typo in the png_set_sRGB() function call in example.c (Jan Nijtmans)
-  Further optimization and bugfix of pngvcrd.c
-  Revised pngset.c so that it does not allocate or free memory in the user's
-    text_ptr structure.  Instead, it makes its own copy.
-  Created separate write_end_info_struct in pngtest.c for a more severe test.
-  Added code in pngwrite.c to free info_ptr->text[i].key to stop a memory leak.
-
-Version 1.0.5b [November 23, 1999]
-  Moved PNG_FLAG_HAVE_CHUNK_HEADER, PNG_FLAG_BACKGROUND_IS_GRAY and
-    PNG_FLAG_WROTE_tIME from flags to mode.
-  Added png_write_info_before_PLTE() function.
-  Fixed some typecasting in contrib/gregbook/*.c
-  Updated scripts/makevms.com and added makevms.com to contrib/gregbook
-    and contrib/pngminus (Martin Zinser)
-
-Version 1.0.5c [November 26, 1999]
-  Moved png_get_header_version from png.h to png.c, to accommodate ansi2knr.
-  Removed all global arrays (according to PNG_NO_GLOBAL_ARRAYS macro), to
-    accommodate making DLL's: Moved usr_png_ver from global variable to function
-    png_get_header_ver() in png.c.  Moved png_sig to png_sig_bytes in png.c and
-    eliminated use of png_sig in pngwutil.c.  Moved the various png_CHNK arrays
-    into pngtypes.h.  Eliminated use of global png_pass arrays.  Declared the
-    png_CHNK and png_pass arrays to be "const".  Made the global arrays
-    available to applications (although none are used in libpng itself) when
-    PNG_NO_GLOBAL_ARRAYS is not defined or when PNG_GLOBAL_ARRAYS is defined.
-  Removed some extraneous "-I" from contrib/pngminus/makefile.std
-  Changed the PNG_sRGB_INTENT macros in png.h to be consistent with PNG-1.2.
-  Change PNG_SRGB_INTENT to PNG_sRGB_INTENT in libpng.txt and libpng.3
-
-Version 1.0.5d [November 29, 1999]
-  Add type cast (png_const_charp) two places in png.c
-  Eliminated pngtypes.h; use macros instead to declare PNG_CHNK arrays.
-  Renamed "PNG_GLOBAL_ARRAYS" to "PNG_USE_GLOBAL_ARRAYS" and made available
-    to applications a macro "PNG_USE_LOCAL_ARRAYS".
-  comment out (with #ifdef) all the new declarations when
-    PNG_USE_GLOBAL_ARRAYS is defined.
-  Added PNG_EXPORT_VAR macro to accommodate making DLL's.
-
-Version 1.0.5e [November 30, 1999]
-  Added iCCP, iTXt, and sPLT support; added "lang" member to the png_text
-    structure; refactored the inflate/deflate support to make adding new chunks
-    with trailing compressed parts easier in the future, and added new functions
-    png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
-    png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
-  NOTE: Applications that write text chunks MUST define png_text->lang
-    before calling png_set_text(). It must be set to NULL if you want to
-    write tEXt or zTXt chunks.  If you want your application to be able to
-    run with older versions of libpng, use
-
-      #ifdef PNG_iTXt_SUPPORTED
-         png_text[i].lang = NULL;
-      #endif
-
-  Changed png_get_oFFs() and png_set_oFFs() to use signed rather than unsigned
-    offsets (Eric S. Raymond).
-  Combined PNG_READ_cHNK_SUPPORTED and PNG_WRITE_cHNK_SUPPORTED macros into
-    PNG_cHNK_SUPPORTED and combined the three types of PNG_text_SUPPORTED
-    macros, leaving the separate macros also available.
-  Removed comments on #endifs at the end of many short, non-nested #if-blocks.
-
-Version 1.0.5f [December 6, 1999]
-  Changed makefile.solaris to issue a warning about potential problems when
-    the ucb "ld" is in the path ahead of the ccs "ld".
-  Removed "- [date]" from the "synopsis" line in libpng.3 and libpngpf.3.
-  Added sCAL chunk support (Eric S. Raymond).
-
-Version 1.0.5g [December 7, 1999]
-  Fixed "png_free_spallettes" typo in png.h
-  Added code to handle new chunks in pngpread.c
-  Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
-  Added "translated_key" to png_text structure and png_write_iTXt().
-  Added code in pngwrite.c to work around a newly discovered zlib bug.
-
-Version 1.0.5h [December 10, 1999]
-  NOTE: regarding the note for version 1.0.5e, the following must also
-    be included in your code:
-        png_text[i].translated_key = NULL;
-  Unknown chunk handling is now supported.
-  Option to eliminate all floating point support was added.  Some new
-    fixed-point functions such as png_set_gAMA_fixed() were added.
-  Expanded tabs and removed trailing blanks in source files.
-
-Version 1.0.5i [December 13, 1999]
-  Added some type casts to silence compiler warnings.
-  Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
-  Removed leading blanks from a #define in pngvcrd.c
-  Added some parameters to the new png_set_keep_unknown_chunks() function.
-  Added a test for up->location != 0 in the first instance of writing
-    unknown chunks in pngwrite.c
-  Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
-    prevent recursion.
-  Added png_free_hIST() function.
-  Various patches to fix bugs in the sCAL and integer cHRM processing,
-    and to add some convenience macros for use with sCAL.
-
-Version 1.0.5j [December 21, 1999]
-  Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
-    around buggy compilers.
-  Added new type "png_fixed_point" for integers that hold float*100000 values
-  Restored backward compatibility of tEXt/zTXt chunk processing:
-    Restored the first four members of png_text to the same order as v.1.0.5d.
-    Added members "lang_key" and "itxt_length" to png_text struct.  Set
-    text_length=0 when "text" contains iTXt data.  Use the "compression"
-    member to distinguish among tEXt/zTXt/iTXt types.  Added
-    PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
-    The "Note" above, about backward incompatibility of libpng-1.0.5e, no
-    longer applies.
-  Fixed png_read|write_iTXt() to read|write parameters in the right order,
-    and to write the iTXt chunk after IDAT if it appears in the end_ptr.
-  Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
-  Reversed the order of trying to write floating-point and fixed-point gAMA.
-
-Version 1.0.5k [December 27, 1999]
-  Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
-  Added png_handle_as_unknown() function (Glenn)
-  Added png_free_chunk_list() function and chunk_list and num_chunk_list members
-    of png_ptr.
-  Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
-  Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
-    about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
-  Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
-  Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
-  Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
-
-Version 1.0.5l [January 1, 2000]
-  Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
-    for setting a callback function to handle unknown chunks and for
-    retrieving the associated user pointer (Glenn).
-
-Version 1.0.5m [January 7, 2000]
-  Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
-
-Version 1.0.5n [January 9, 2000]
-  Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
-    own memory for info_ptr->palette.  This makes it safe for the calling
-    application to free its copy of the palette any time after it calls
-    png_set_PLTE().
-
-Version 1.0.5o [January 20, 2000]
-  Cosmetic changes only (removed some trailing blanks and TABs)
-
-Version 1.0.5p [January 31, 2000]
-  Renamed pngdll.mak to makefile.bd32
-  Cosmetic changes in pngtest.c
-
-Version 1.0.5q [February 5, 2000]
-  Relocated the makefile.solaris warning about PATH problems.
-  Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
-  Revised makefile.gcmmx
-  Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
-
-Version 1.0.5r [February 7, 2000]
-  Removed superfluous prototype for png_get_itxt from png.h
-  Fixed a bug in pngrtran.c that improperly expanded the background color.
-  Return *num_text=0 from png_get_text() when appropriate, and fix documentation
-    of png_get_text() in libpng.txt/libpng.3.
-
-Version 1.0.5s [February 18, 2000]
-  Added "png_jmp_env()" macro to pngconf.h, to help people migrate to the
-    new error handler that's planned for the next libpng release, and changed
-    example.c, pngtest.c, and contrib programs to use this macro.
-  Revised some of the DLL-export macros in pngconf.h (Greg Roelofs)
-  Fixed a bug in png_read_png() that caused it to fail to expand some images
-    that it should have expanded.
-  Fixed some mistakes in the unused and undocumented INCH_CONVERSIONS functions
-    in pngget.c
-  Changed the allocation of palette, history, and trans arrays back to
-    the version 1.0.5 method (linking instead of copying) which restores
-    backward compatibility with version 1.0.5.  Added some remarks about
-    that in example.c.  Added "free_me" member to info_ptr and png_ptr
-    and added png_free_data() function.
-  Updated makefile.linux and makefile.gccmmx to make directories conditionally.
-  Made cosmetic changes to pngasmrd.h
-  Added png_set_rows() and png_get_rows(), for use with png_read|write_png().
-  Modified png_read_png() to allocate info_ptr->row_pointers only if it
-    hasn't already been allocated.
-
-Version 1.0.5t [March 4, 2000]
-  Changed png_jmp_env() migration aiding macro to png_jmpbuf().
-  Fixed "interlace" typo (should be "interlaced") in contrib/gregbook/read2-x.c
-  Fixed bug with use of PNG_BEFORE_IHDR bit in png_ptr->mode, introduced when
-    PNG_FLAG_HAVE_CHUNK_HEADER was moved into png_ptr->mode in version 1.0.5b
-  Files in contrib/gregbook were revised to use png_jmpbuf() and to select
-    a 24-bit visual if one is available, and to allow abbreviated options.
-  Files in contrib/pngminus were revised to use the png_jmpbuf() macro.
-  Removed spaces in makefile.linux and makefile.gcmmx, introduced in 1.0.5s
-
-Version 1.0.5u [March 5, 2000]
-  Simplified the code that detects old png.h in png.c and pngtest.c
-  Renamed png_spalette (_p, _pp) to png_sPLT_t (_tp, _tpp)
-  Increased precision of rgb_to_gray calculations from 8 to 15 bits and
-    added png_set_rgb_to_gray_fixed() function.
-  Added makefile.bc32 (32-bit Borland C++, C mode)
-
-Version 1.0.5v [March 11, 2000]
-  Added some parentheses to the png_jmpbuf macro definition.
-  Updated references to the zlib home page, which has moved to freesoftware.com.
-  Corrected bugs in documentation regarding png_read_row() and png_write_row().
-  Updated documentation of png_rgb_to_gray calculations in libpng.3/libpng.txt.
-  Renamed makefile.borland,turboc3 back to makefile.bor,tc3 as in version 1.0.3,
-    revised borland makefiles; added makefile.ibmvac3 and makefile.gcc (Cosmin)
-
-Version 1.0.6 [March 20, 2000]
-  Minor revisions of makefile.bor, libpng.txt, and gregbook/rpng2-win.c
-  Added makefile.sggcc (SGI IRIX with gcc)
-
-Version 1.0.6d [April 7, 2000]
-  Changed sprintf() to strcpy() in png_write_sCAL_s() to work without STDIO
-  Added data_length parameter to png_decompress_chunk() function
-  Revised documentation to remove reference to abandoned png_free_chnk functions
-  Fixed an error in png_rgb_to_gray_fixed()
-  Revised example.c, usage of png_destroy_write_struct().
-  Renamed makefile.ibmvac3 to makefile.ibmc, added libpng.icc IBM project file
-  Added a check for info_ptr->free_me&PNG_FREE_TEXT when freeing text in png.c
-  Simplify png_sig_bytes() function to remove use of non-ISO-C strdup().
-
-Version 1.0.6e [April 9, 2000]
-  Added png_data_freer() function.
-  In the code that checks for over-length tRNS chunks, added check of
-    info_ptr->num_trans as well as png_ptr->num_trans (Matthias Benckmann)
-  Minor revisions of libpng.txt/libpng.3.
-  Check for existing data and free it if the free_me flag is set, in png_set_*()
-    and png_handle_*().
-  Only define PNG_WEIGHTED_FILTERS_SUPPORTED when PNG_FLOATING_POINT_SUPPORTED
-    is defined.
-  Changed several instances of PNG_NO_CONSOLE_ID to PNG_NO_STDIO in pngrutil.c
-    and mentioned the purposes of the two macros in libpng.txt/libpng.3.
-
-Version 1.0.6f [April 14, 2000]
-  Revised png_set_iCCP() and png_set_rows() to avoid prematurely freeing data.
-  Add checks in png_set_text() for NULL members of the input text structure.
-  Revised libpng.txt/libpng.3.
-  Removed superfluous prototype for png_set_iTXt from png.h
-  Removed "else" from pngread.c, after png_error(), and changed "0" to "length".
-  Changed several png_errors about malformed ancillary chunks to png_warnings.
-
-Version 1.0.6g [April 24, 2000]
-  Added png_pass-* arrays to pnggccrd.c when PNG_USE_LOCAL_ARRAYS is defined.
-  Relocated paragraph about png_set_background() in libpng.3/libpng.txt
-    and other revisions (Matthias Benckmann)
-  Relocated info_ptr->free_me, png_ptr->free_me, and other info_ptr and
-    png_ptr members to restore binary compatibility with libpng-1.0.5
-    (breaks compatibility with libpng-1.0.6).
-
-Version 1.0.6h [April 24, 2000]
-  Changed shared library so-number pattern from 2.x.y.z to xy.z (this builds
-    libpng.so.10 & libpng.so.10.6h instead of libpng.so.2 & libpng.so.2.1.0.6h)
-    This is a temporary change for test purposes.
-
-Version 1.0.6i [May 2, 2000]
-  Rearranged some members at the end of png_info and png_struct, to put
-    unknown_chunks_num and free_me within the original size of the png_structs
-    and free_me, png_read_user_fn, and png_free_fn within the original png_info,
-    because some old applications allocate the structs directly instead of
-    using png_create_*().
-  Added documentation of user memory functions in libpng.txt/libpng.3
-  Modified png_read_png so that it will use user_allocated row_pointers
-    if present, unless free_me directs that it be freed, and added description
-    of the use of png_set_rows() and png_get_rows() in libpng.txt/libpng.3.
-  Added PNG_LEGACY_SUPPORTED macro, and #ifdef out all new (since version
-    1.00) members of png_struct and png_info, to regain binary compatibility
-    when you define this macro.  Capabilities lost in this event
-    are user transforms (new in version 1.0.0),the user transform pointer
-    (new in version 1.0.2), rgb_to_gray (new in 1.0.5), iCCP, sCAL, sPLT,
-    the high-level interface, and unknown chunks support (all new in 1.0.6).
-    This was necessary because of old applications that allocate the structs
-    directly as authors were instructed to do in libpng-0.88 and earlier,
-    instead of using png_create_*().
-  Added modes PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT which
-    can be used to detect codes that directly allocate the structs, and
-    code to check these modes in png_read_init() and png_write_init() and
-    generate a libpng error if the modes aren't set and PNG_LEGACY_SUPPORTED
-    was not defined.
-  Added makefile.intel and updated makefile.watcom (Pawel Mrochen)
-
-Version 1.0.6j [May 3, 2000]
-  Overloaded png_read_init() and png_write_init() with macros that convert
-    calls to png_read_init_2() or png_write_init_2() that check the version
-    and structure sizes.
-
-Version 1.0.7beta11 [May 7, 2000]
-  Removed the new PNG_CREATED_READ_STRUCT and PNG_CREATED_WRITE_STRUCT modes
-    which are no longer used.
-  Eliminated the three new members of png_text when PNG_LEGACY_SUPPORTED is
-    defined or when neither PNG_READ_iTXt_SUPPORTED nor PNG_WRITE_iTXT_SUPPORTED
-    is defined.
-  Made PNG_NO_READ|WRITE_iTXt the default setting, to avoid memory
-    overrun when old applications fill the info_ptr->text structure directly.
-  Added PNGAPI macro, and added it to the definitions of all exported functions.
-  Relocated version macro definitions ahead of the includes of zlib.h and
-    pngconf.h in png.h.
-
-Version 1.0.7beta12 [May 12, 2000]
-  Revised pngset.c to avoid a problem with expanding the png_debug macro.
-  Deleted some extraneous defines from pngconf.h
-  Made PNG_NO_CONSOLE_IO the default condition when PNG_BUILD_DLL is defined.
-  Use MSC _RPTn debugging instead of fprintf if _MSC_VER is defined.
-  Added png_access_version_number() function.
-  Check for mask&PNG_FREE_CHNK (for TEXT, SCAL, PCAL) in png_free_data().
-  Expanded libpng.3/libpng.txt information about png_data_freer().
-
-Version 1.0.7beta14 [May 17, 2000] (beta13 was not published)
-  Changed pnggccrd.c and pngvcrd.c to handle bad adaptive filter types as
-    warnings instead of errors, as pngrutil.c does.
-  Set the PNG_INFO_IDAT valid flag in png_set_rows() so png_write_png()
-    will actually write IDATs.
-  Made the default PNG_USE_LOCAL_ARRAYS depend on PNG_DLL instead of WIN32.
-  Make png_free_data() ignore its final parameter except when freeing data
-    that can have multiple instances (text, sPLT, unknowns).
-  Fixed a new bug in png_set_rows().
-  Removed info_ptr->valid tests from png_free_data(), as in version 1.0.5.
-  Added png_set_invalid() function.
-  Fixed incorrect illustrations of png_destroy_write_struct() in example.c.
-
-Version 1.0.7beta15 [May 30, 2000]
-  Revised the deliberately erroneous Linux setjmp code in pngconf.h to produce
-    fewer error messages.
-  Rearranged checks for Z_OK to check the most likely path first in pngpread.c
-    and pngwutil.c.
-  Added checks in pngtest.c for png_create_*() returning NULL, and mentioned
-    in libpng.txt/libpng.3 the need for applications to check this.
-  Changed names of png_default_*() functions in pngtest to pngtest_*().
-  Changed return type of png_get_x|y_offset_*() from png_uint_32 to png_int_32.
-  Fixed some bugs in the unused PNG_INCH_CONVERSIONS functions in pngget.c
-  Set each pointer to NULL after freeing it in png_free_data().
-  Worked around a problem in pngconf.h; AIX's strings.h defines an "index"
-    macro that conflicts with libpng's png_color_16.index. (Dimitri
-    Papadapoulos)
-  Added "msvc" directory with MSVC++ project files (Simon-Pierre Cadieux).
-
-Version 1.0.7beta16 [June 4, 2000]
-  Revised the workaround of AIX string.h "index" bug.
-  Added a check for overlength PLTE chunk in pngrutil.c.
-  Added PNG_NO_POINTER_INDEXING macro to use array-indexing instead of pointer
-    indexing in pngrutil.c and pngwutil.c to accommodate a buggy compiler.
-  Added a warning in png_decompress_chunk() when it runs out of data, e.g.
-    when it tries to read an erroneous PhotoShop iCCP chunk.
-  Added PNG_USE_DLL macro.
-  Revised the copyright/disclaimer/license notice.
-  Added contrib/msvctest directory
-
-Version 1.0.7rc1 [June 9, 2000]
-  Corrected the definition of PNG_TRANSFORM_INVERT_ALPHA  (0x0400 not 0x0200)
-  Added contrib/visupng directory (Willem van Schaik)
-
-Version 1.0.7beta18 [June 23, 2000]
-  Revised PNGAPI definition, and pngvcrd.c to work with __GCC__
-    and do not redefine PNGAPI if it is passed in via a compiler directive.
-  Revised visupng/PngFile.c to remove returns from within the Try block.
-  Removed leading underscores from "_PNG_H" and "_PNG_SAVE_BSD_SOURCE" macros.
-  Updated contrib/visupng/cexcept.h to version 1.0.0.
-  Fixed bugs in pngwrite.c and pngwutil.c that prevented writing iCCP chunks.
-
-Version 1.0.7rc2 [June 28, 2000]
-  Updated license to include disclaimers required by UCITA.
-  Fixed "DJBPP" typo in pnggccrd.c introduced in beta18.
-
-Version 1.0.7 [July 1, 2000]
-  Revised the definition of "trans_values" in libpng.3/libpng.txt
-
-Version 1.0.8beta1 [July 8, 2000]
-  Added png_free(png_ptr, key) two places in pngpread.c to stop memory leaks.
-  Changed PNG_NO_STDIO to PNG_NO_CONSOLE_IO, several places in pngrutil.c and
-    pngwutil.c.
-  Changed PNG_EXPORT_VAR to use PNG_IMPEXP, in pngconf.h.
-  Removed unused "#include <assert.h>" from png.c
-  Added WindowsCE support.
-  Revised pnggccrd.c to work with gcc-2.95.2 and in the Cygwin environment.
-
-Version 1.0.8beta2 [July 10, 2000]
-  Added project files to the wince directory and made further revisions
-    of pngtest.c, pngrio.c, and pngwio.c in support of WindowsCE.
-
-Version 1.0.8beta3 [July 11, 2000]
-  Only set the PNG_FLAG_FREE_TRNS or PNG_FREE_TRNS flag in png_handle_tRNS()
-    for indexed-color input files to avoid potential double-freeing trans array
-    under some unusual conditions; problem was introduced in version 1.0.6f.
-  Further revisions to pngtest.c and files in the wince subdirectory.
-
-Version 1.0.8beta4 [July 14, 2000]
-  Added the files pngbar.png and pngbar.jpg to the distribution.
-  Added makefile.cygwin, and cygwin support in pngconf.h
-  Added PNG_NO_ZALLOC_ZERO macro (makes png_zalloc skip zeroing memory)
-
-Version 1.0.8rc1 [July 16, 2000]
-  Revised png_debug() macros and statements to eliminate compiler warnings.
-
-Version 1.0.8 [July 24, 2000]
-  Added png_flush() in pngwrite.c, after png_write_IEND().
-  Updated makefile.hpux to build a shared library.
-
-Version 1.0.9beta1 [November 10, 2000]
-  Fixed typo in scripts/makefile.hpux
-  Updated makevms.com in scripts and contrib/* and contrib/* (Martin Zinser)
-  Fixed seqence-point bug in contrib/pngminus/png2pnm (Martin Zinser)
-  Changed "cdrom.com" in documentation to "libpng.org"
-  Revised pnggccrd.c to get it all working, and updated makefile.gcmmx (Greg).
-  Changed type of "params" from voidp to png_voidp in png_read|write_png().
-  Make sure PNGAPI and PNG_IMPEXP are defined in pngconf.h.
-  Revised the 3 instances of WRITEFILE in pngtest.c.
-  Relocated "msvc" and "wince" project subdirectories into "dll" subdirectory.
-  Updated png.rc in dll/msvc project
-  Revised makefile.dec to define and use LIBPATH and INCPATH
-  Increased size of global png_libpng_ver[] array from 12 to 18 chars.
-  Made global png_libpng_ver[], png_sig[] and png_pass_*[] arrays const.
-  Removed duplicate png_crc_finish() from png_handle_bKGD() function.
-  Added a warning when application calls png_read_update_info() multiple times.
-  Revised makefile.cygwin
-  Fixed bugs in iCCP support in pngrutil.c and pngwutil.c.
-  Replaced png_set_empty_plte_permitted() with png_permit_mng_features().
-
-Version 1.0.9beta2 [November 19, 2000]
-  Renamed the "dll" subdirectory "projects".
-  Added borland project files to "projects" subdirectory.
-  Set VS_FF_PRERELEASE and VS_FF_PATCHED flags in msvc/png.rc when appropriate.
-  Add error message in png_set_compression_buffer_size() when malloc fails.
-
-Version 1.0.9beta3 [November 23, 2000]
-  Revised PNG_LIBPNG_BUILD_TYPE macro in png.h, used in the msvc project.
-  Removed the png_flush() in pngwrite.c that crashes some applications
-    that don't set png_output_flush_fn.
-  Added makefile.macosx and makefile.aix to scripts directory.
-
-Version 1.0.9beta4 [December 1, 2000]
-  Change png_chunk_warning to png_warning in png_check_keyword().
-  Increased the first part of msg buffer from 16 to 18 in png_chunk_error().
-
-Version 1.0.9beta5 [December 15, 2000]
-  Added support for filter method 64 (for PNG datastreams embedded in MNG).
-
-Version 1.0.9beta6 [December 18, 2000]
-  Revised png_set_filter() to accept filter method 64 when appropriate.
-  Added new PNG_HAVE_PNG_SIGNATURE bit to png_ptr->mode and use it to
-    help prevent applications from using MNG features in PNG datastreams.
-  Added png_permit_mng_features() function.
-  Revised libpng.3/libpng.txt.  Changed "filter type" to "filter method".
-
-Version 1.0.9rc1 [December 23, 2000]
-  Revised test for PNG_HAVE_PNG_SIGNATURE in pngrutil.c
-  Fixed error handling of unknown compression type in png_decompress_chunk().
-  In pngconf.h, define __cdecl when _MSC_VER is defined.
-
-Version 1.0.9beta7 [December 28, 2000]
-  Changed PNG_TEXT_COMPRESSION_zTXt to PNG_COMPRESSION_TYPE_BASE several places.
-  Revised memory management in png_set_hIST and png_handle_hIST in a backward
-    compatible manner.  PLTE and tRNS were revised similarly.
-  Revised the iCCP chunk reader to ignore trailing garbage.
-
-Version 1.0.9beta8 [January 12, 2001]
-  Moved pngasmrd.h into pngconf.h.
-  Improved handling of out-of-spec garbage iCCP chunks generated by PhotoShop.
-
-Version 1.0.9beta9 [January 15, 2001]
-  Added png_set_invalid, png_permit_mng_features, and png_mmx_supported to
-    wince and msvc project module definition files.
-  Minor revision of makefile.cygwin.
-  Fixed bug with progressive reading of narrow interlaced images in pngpread.c
-
-Version 1.0.9beta10 [January 16, 2001]
-  Do not typedef png_FILE_p in pngconf.h when PNG_NO_STDIO is defined.
-  Fixed "png_mmx_supported" typo in project definition files.
-
-Version 1.0.9beta11 [January 19, 2001]
-  Updated makefile.sgi to make shared library.
-  Removed png_mmx_support() function and disabled PNG_MNG_FEATURES_SUPPORTED
-    by default, for the benefit of DLL forward compatibility.  These will
-    be re-enabled in version 1.2.0.
-
-Version 1.0.9rc2 [January 22, 2001]
-  Revised cygwin support.
-
-Version 1.0.9 [January 31, 2001]
-  Added check of cygwin's ALL_STATIC in pngconf.h
-  Added "-nommx" parameter to contrib/gregbook/rpng2-win and rpng2-x demos.
-
-Version 1.0.10beta1 [March 14, 2001]
-  Revised makefile.dec, makefile.sgi, and makefile.sggcc; added makefile.hpgcc.
-  Reformatted libpng.3 to eliminate bad line breaks.
-  Added checks for _mmx_supported in the read_filter_row function of pnggccrd.c
-  Added prototype for png_mmx_support() near the top of pnggccrd.c
-  Moved some error checking from png_handle_IHDR to png_set_IHDR.
-  Added PNG_NO_READ_SUPPORTED and PNG_NO_WRITE_SUPPORTED macros.
-  Revised png_mmx_support() function in pnggccrd.c
-  Restored version 1.0.8 PNG_WRITE_EMPTY_PLTE_SUPPORTED behavior in pngwutil.c
-  Fixed memory leak in contrib/visupng/PngFile.c
-  Fixed bugs in png_combine_row() in pnggccrd.c and pngvcrd.c (C version)
-  Added warnings when retrieving or setting gamma=0.
-  Increased the first part of msg buffer from 16 to 18 in png_chunk_warning().
-
-Version 1.0.10rc1 [March 23, 2001]
-  Changed all instances of memcpy, strcpy, and strlen to png_memcpy, png_strcpy,
-    and png_strlen.
-  Revised png_mmx_supported() function in pnggccrd.c to return proper value.
-  Fixed bug in progressive reading (pngpread.c) with small images (height < 8).
-
-Version 1.0.10 [March 30, 2001]
-  Deleted extraneous space (introduced in 1.0.9) from line 42 of makefile.cygwin
-  Added beos project files (Chris Herborth)
-
-Version 1.0.11beta1 [April 3, 2001]
-  Added type casts on several png_malloc() calls (Dimitri Papadapoulos).
-  Removed a no-longer needed AIX work-around from pngconf.h
-  Changed several "//" single-line comments to C-style in pnggccrd.c
-
-Version 1.0.11beta2 [April 11, 2001]
-  Removed PNGAPI from several functions whose prototypes did not have PNGAPI.
-  Updated scripts/pngos2.def
-
-Version 1.0.11beta3 [April 14, 2001]
-  Added checking the results of many instances of png_malloc() for NULL
-
-Version 1.0.11beta4 [April 20, 2001]
-  Undid the changes from version 1.0.11beta3.  Added a check for NULL return
-    from user's malloc_fn().
-  Removed some useless type casts of the NULL pointer.
-  Added makefile.netbsd
-
-Version 1.0.11 [April 27, 2001]
-  Revised makefile.netbsd
-
-Version 1.0.12beta1 [May 14, 2001]
-  Test for Windows platform in pngconf.h when including malloc.h (Emmanuel Blot)
-  Updated makefile.cygwin and handling of Cygwin's ALL_STATIC in pngconf.h
-  Added some never-to-be-executed code in pnggccrd.c to quiet compiler warnings.
-  Eliminated the png_error about apps using png_read|write_init().  Instead,
-    libpng will reallocate the png_struct and info_struct if they are too small.
-    This retains future binary compatibility for old applications written for
-    libpng-0.88 and earlier.
-
-Version 1.2.0beta1 [May 6, 2001]
-  Bumped DLLNUM to 2.
-  Re-enabled PNG_MNG_FEATURES_SUPPORTED and enabled PNG_ASSEMBLER_CODE_SUPPORTED
-    by default.
-  Added runtime selection of MMX features.
-  Added png_set_strip_error_numbers function and related macros.
-
-Version 1.2.0beta2 [May 7, 2001]
-  Finished merging 1.2.0beta1 with version 1.0.11
-  Added a check for attempts to read or write PLTE in grayscale PNG datastreams.
-
-Version 1.2.0beta3 [May 17, 2001]
-  Enabled user memory function by default.
-  Modified png_create_struct so it passes user mem_ptr to user memory allocator.
-  Increased png_mng_features flag from png_byte to png_uint_32.
-  Bumped shared-library (so-number) and dll-number to 3.
-
-Version 1.2.0beta4 [June 23, 2001]
-  Check for missing profile length field in iCCP chunk and free chunk_data
-    in case of truncated iCCP chunk.
-  Bumped shared-library number to 3 in makefile.sgi and makefile.sggcc
-  Bumped dll-number from 2 to 3 in makefile.cygwin
-  Revised contrib/gregbook/rpng*-x.c to avoid a memory leak and to exit cleanly
-    if user attempts to run it on an 8-bit display.
-  Updated contrib/gregbook
-  Use png_malloc instead of png_zalloc to allocate palette in pngset.c
-  Updated makefile.ibmc
-  Added some typecasts to eliminate gcc 3.0 warnings.  Changed prototypes
-    of png_write_oFFS width and height from png_uint_32 to png_int_32.
-  Updated example.c
-  Revised prototypes for png_debug_malloc and png_debug_free in pngtest.c
-
-Version 1.2.0beta5 [August 8, 2001]
-  Revised contrib/gregbook
-  Revised makefile.gcmmx
-  Revised pnggccrd.c to conditionally compile some thread-unsafe code only
-    when PNG_THREAD_UNSAFE_OK is defined.
-  Added tests to prevent pngwutil.c from writing a bKGD or tRNS chunk with
-    value exceeding 2^bit_depth-1
-  Revised makefile.sgi and makefile.sggcc
-  Replaced calls to fprintf(stderr,...) with png_warning() in pnggccrd.c
-  Removed restriction that do_invert_mono only operate on 1-bit opaque files
-
-Version 1.2.0 [September 1, 2001]
-  Changed a png_warning() to png_debug() in pnggccrd.c
-  Fixed contrib/gregbook/rpng-x.c, rpng2-x.c to avoid crash with XFreeGC().
-
-Version 1.2.1beta1 [October 19, 2001]
-  Revised makefile.std in contrib/pngminus
-  Include background_1 in png_struct regardless of gamma support.
-  Revised makefile.netbsd and makefile.macosx, added makefile.darwin.
-  Revised example.c to provide more details about using row_callback().
-
-Version 1.2.1beta2 [October 25, 2001]
-  Added type cast to each NULL appearing in a function call, except for
-    WINCE functions.
-  Added makefile.so9.
-
-Version 1.2.1beta3 [October 27, 2001]
-  Removed type casts from all NULLs.
-  Simplified png_create_struct_2().
-
-Version 1.2.1beta4 [November 7, 2001]
-  Revised png_create_info_struct() and png_creat_struct_2().
-  Added error message if png_write_info() was omitted.
-  Type cast NULLs appearing in function calls when _NO_PROTO or
-    PNG_TYPECAST_NULL is defined.
-
-Version 1.2.1rc1 [November 24, 2001]
-  Type cast NULLs appearing in function calls except when PNG_NO_TYPECAST_NULL
-    is defined.
-  Changed typecast of "size" argument to png_size_t in pngmem.c calls to
-    the user malloc_fn, to agree with the prototype in png.h
-  Added a pop/push operation to pnggccrd.c, to preserve Eflag (Maxim Sobolev)
-  Updated makefile.sgi to recognize LIBPATH and INCPATH.
-  Updated various makefiles so "make clean" does not remove previous major
-    version of the shared library.
-
-Version 1.2.1rc2 [December 4, 2001]
-  Always allocate 256-entry internal palette, hist, and trans arrays, to
-    avoid out-of-bounds memory reference caused by invalid PNG datastreams.
-  Added a check for prefix_length > data_length in iCCP chunk handler.
-
-Version 1.2.1 [December 7, 2001]
-  None.
-
-Version 1.2.2beta1 [February 22, 2002]
-  Fixed a bug with reading the length of iCCP profiles (Larry Reeves).
-  Revised makefile.linux, makefile.gcmmx, and makefile.sgi to generate
-    libpng.a, libpng12.so (not libpng.so.3), and libpng12/png.h
-  Revised makefile.darwin to remove "-undefined suppress" option.
-  Added checks for gamma and chromaticity values over 21474.83, which exceed
-    the limit for PNG unsigned 32-bit integers when encoded.
-  Revised calls to png_create_read_struct() and png_create_write_struct()
-    for simpler debugging.
-  Revised png_zalloc() so zlib handles errors (uses PNG_FLAG_MALLOC_NULL_MEM_OK)
-
-Version 1.2.2beta2 [February 23, 2002]
-  Check chunk_length and idat_size for invalid (over PNG_MAX_UINT) lengths.
-  Check for invalid image dimensions in png_get_IHDR.
-  Added missing "fi;" in the install target of the SGI makefiles.
-  Added install-static to all makefiles that make shared libraries.
-  Always do gamma compensation when image is partially transparent.
-
-Version 1.2.2beta3 [March 7, 2002]
-  Compute background.gray and background_1.gray even when color_type is RGB
-    in case image gets reduced to gray later.
-  Modified shared-library makefiles to install pkgconfig/libpngNN.pc.
-  Export (with PNGAPI) png_zalloc, png_zfree, and png_handle_as_unknown
-  Removed unused png_write_destroy_info prototype from png.h
-  Eliminated incorrect use of width_mmx from pnggccrd.c in pixel_bytes == 8 case
-  Added install-shared target to all makefiles that make shared libraries.
-  Stopped a double free of palette, hist, and trans when not using free_me.
-  Added makefile.32sunu for Sun Ultra 32 and makefile.64sunu for Sun Ultra 64.
-
-Version 1.2.2beta4 [March 8, 2002]
-  Compute background.gray and background_1.gray even when color_type is RGB
-    in case image gets reduced to gray later (Jason Summers).
-  Relocated a misplaced /bin/rm in the "install-shared" makefile targets
-  Added PNG_1_0_X macro which can be used to build a 1.0.x-compatible library.
-
-Version 1.2.2beta5 [March 26, 2002]
-  Added missing PNGAPI to several function definitions.
-  Check for invalid bit_depth or color_type in png_get_IHDR(), and
-    check for missing PLTE or IHDR in png_push_read_chunk() (Matthias Clasen).
-  Revised iTXt support to accept NULL for lang and lang_key.
-  Compute gamma for color components of background even when color_type is gray.
-  Changed "()" to "{}" in scripts/libpng.pc.in.
-  Revised makefiles to put png.h and pngconf.h only in $prefix/include/libpngNN
-  Revised makefiles to make symlink to libpng.so.NN in addition to libpngNN.so
-
-Version 1.2.2beta6 [March 31, 2002]
-
-Version 1.0.13beta1 [March 31, 2002]
-  Prevent png_zalloc() from trying to memset memory that it failed to acquire.
-  Add typecasts of PNG_MAX_UINT in pngset_cHRM_fixed() (Matt Holgate).
-  Ensure that the right function (user or default) is used to free the
-    png_struct after an error in png_create_read_struct_2().
-
-Version 1.2.2rc1 [April 7, 2002]
-
-Version 1.0.13rc1 [April 7, 2002]
-  Save the ebx register in pnggccrd.c (Sami Farin)
-  Add "mem_ptr = png_ptr->mem_ptr" in png_destroy_write_struct() (Paul Gardner).
-  Updated makefiles to put headers in include/libpng and remove old include/*.h.
-
-Version 1.2.2 [April 15, 2002]
-
-Version 1.0.13 [April 15, 2002]
-  Revised description of png_set_filter() in libpng.3/libpng.txt.
-  Revised makefile.netbsd and added makefile.neNNbsd and makefile.freebsd
-
-Version 1.0.13patch01 [April 17, 2002]
-
-Version 1.2.2patch01 [April 17, 2002]
-  Changed ${PNGMAJ}.${PNGVER} bug to ${PNGVER} in makefile.sgi and
-    makefile.sggcc
-  Fixed VER -> PNGVER typo in makefile.macosx and added install-static to
-    install
-  Added install: target to makefile.32sunu and makefile.64sunu
-
-Version 1.0.13patch03 [April 18, 2002]
-
-Version 1.2.2patch03 [April 18, 2002]
-  Revised 15 makefiles to link libpng.a to libpngNN.a and the include libpng
-  subdirectory to libpngNN subdirectory without the full pathname.
-  Moved generation of libpng.pc from "install" to "all" in 15 makefiles.
-
-Version 1.2.3rc1 [April 28, 2002]
-  Added install-man target to 15 makefiles (Dimitri Papadopolous-Orfanos).
-  Added $(DESTDIR) feature to 24 makefiles (Tim Mooney)
-  Fixed bug with $prefix, should be $(prefix) in makefile.hpux.
-  Updated cygwin-specific portion of pngconf.h and revised makefile.cygwin
-  Added a link from libpngNN.pc to libpng.pc in 15 makefiles.
-  Added links from include/libpngNN/*.h to include/*.h in 24 makefiles.
-  Revised makefile.darwin to make relative links without full pathname.
-  Added setjmp() at the end of png_create_*_struct_2() in case user forgets
-    to put one in their application.
-  Restored png_zalloc() and png_zfree() prototypes to version 1.2.1 and
-    removed them from module definition files.
-
-Version 1.2.3rc2 [May 1, 2002]
-  Fixed bug in reporting number of channels in pngget.c and pngset.c,
-    that was introduced in version 1.2.2beta5.
-  Exported png_zalloc(), png_zfree(), png_default_read(), png_default_write(),
-    png_default_flush(), and png_push_fill_buffer() and included them in
-    module definition files.
-  Added "libpng.pc" dependency to the "install-shared" target in 15 makefiles.
-
-Version 1.2.3rc3 [May 1, 2002]
-  Revised prototype for png_default_flush()
-  Remove old libpng.pc and libpngNN.pc before installing new ones.
-
-Version 1.2.3rc4 [May 2, 2002]
-  Typos in *.def files (png_default_read|write -> png_default_read|write_data)
-  In makefiles, changed rm libpng.NN.pc to rm libpngNN.pc
-  Added libpng-config and libpngNN-config and modified makefiles to install
-    them.
-  Changed $(MANPATH) to $(DESTDIR)$(MANPATH) in makefiles
-  Added "Win32 DLL VB" configuration to projects/msvc/libpng.dsp
-
-Version 1.2.3rc5 [May 11, 2002]
-  Changed "error" and "message" in prototypes to "error_message" and
-    "warning_message" to avoid namespace conflict.
-  Revised 15 makefiles to build libpng-config from libpng-config-*.in
-  Once more restored png_zalloc and png_zfree to regular nonexported form.
-  Restored png_default_read|write_data, png_default_flush, png_read_fill_buffer
-    to nonexported form, but with PNGAPI, and removed them from module def
-    files.
-
-Version 1.2.3rc6 [May 14, 2002]
-  Removed "PNGAPI" from png_zalloc() and png_zfree() in png.c
-  Changed "Gz" to "Gd" in projects/msvc/libpng.dsp and zlib.dsp.
-  Removed leftover libpng-config "sed" script from four makefiles.
-  Revised libpng-config creating script in 16 makefiles.
-
-Version 1.2.3 [May 22, 2002]
-  Revised libpng-config target in makefile.cygwin.
-  Removed description of png_set_mem_fn() from documentation.
-  Revised makefile.freebsd.
-  Minor cosmetic changes to 15 makefiles, e.g., $(DI) = $(DESTDIR)/$(INCDIR).
-  Revised projects/msvc/README.txt
-  Changed -lpng to -lpngNN in LDFLAGS in several makefiles.
-
-Version 1.2.4beta1 [May 24, 2002]
-  Added libpng.pc and libpng-config to "all:" target in 16 makefiles.
-  Fixed bug in 16 makefiles: $(DESTDIR)/$(LIBPATH) to $(DESTDIR)$(LIBPATH)
-  Added missing "\" before closing double quote in makefile.gcmmx.
-  Plugged various memory leaks; added png_malloc_warn() and png_set_text_2()
-    functions.
-
-Version 1.2.4beta2 [June 25, 2002]
-  Plugged memory leak of png_ptr->current_text (Matt Holgate).
-  Check for buffer overflow before reading CRC in pngpread.c (Warwick Allison)
-  Added -soname to the loader flags in makefile.dec, makefile.sgi, and
-    makefile.sggcc.
-  Added "test-installed" target to makefile.linux, makefile.gcmmx,
-    makefile.sgi, and makefile.sggcc.
-
-Version 1.2.4beta3 [June 28, 2002]
-  Plugged memory leak of row_buf in pngtest.c when there is a png_error().
-  Detect buffer overflow in pngpread.c when IDAT is corrupted with extra data.
-  Added "test-installed" target to makefile.32sunu, makefile.64sunu,
-    makefile.beos, makefile.darwin, makefile.dec, makefile.macosx,
-    makefile.solaris, makefile.hpux, makefile.hpgcc, and makefile.so9.
-
-Version 1.2.4rc1 and 1.0.14rc1 [July 2, 2002]
-  Added "test-installed" target to makefile.cygwin and makefile.sco.
-  Revised pnggccrd.c to be able to back out version 1.0.x via PNG_1_0_X macro.
-
-Version 1.2.4 and 1.0.14 [July 8, 2002]
-  Changed png_warning() to png_error() when width is too large to process.
-
-Version 1.2.4patch01 [July 20, 2002]
-  Revised makefile.cygwin to use DLL number 12 instead of 13.
-
-Version 1.2.5beta1 [August 6, 2002]
-  Added code to contrib/gregbook/readpng2.c to ignore unused chunks.
-  Replaced toucan.png in contrib/gregbook (it has been corrupt since 1.0.11)
-  Removed some stray *.o files from contrib/gregbook.
-  Changed png_error() to png_warning() about "Too much data" in pngpread.c
-    and about "Extra compressed data" in pngrutil.c.
-  Prevent png_ptr->pass from exceeding 7 in png_push_finish_row().
-  Updated makefile.hpgcc
-  Updated png.c and pnggccrd.c handling of return from png_mmx_support()
-
-Version 1.2.5beta2 [August 15, 2002]
-  Only issue png_warning() about "Too much data" in pngpread.c when avail_in
-    is nonzero.
-  Updated makefiles to install a separate libpng.so.3 with its own rpath.
-
-Version 1.2.5rc1 and 1.0.15rc1 [August 24, 2002]
-  Revised makefiles to not remove previous minor versions of shared libraries.
-
-Version 1.2.5rc2 and 1.0.15rc2 [September 16, 2002]
-  Revised 13 makefiles to remove "-lz" and "-L$(ZLIBLIB)", etc., from shared
-    library loader directive.
-  Added missing "$OBJSDLL" line to makefile.gcmmx.
-  Added missing "; fi" to makefile.32sunu.
-
-Version 1.2.5rc3 and 1.0.15rc3 [September 18, 2002]
-  Revised libpng-config script.
-
-Version 1.2.5 and 1.0.15 [October 3, 2002]
-  Revised makefile.macosx, makefile.darwin, makefile.hpgcc, and makefile.hpux,
-    and makefile.aix.
-  Relocated two misplaced PNGAPI lines in pngtest.c
-
-Version 1.2.6beta1 [October 22, 2002]
-  Commented out warning about uninitialized mmx_support in pnggccrd.c.
-  Changed "IBMCPP__" flag to "__IBMCPP__" in pngconf.h.
-  Relocated two more misplaced PNGAPI lines in pngtest.c
-  Fixed memory overrun bug in png_do_read_filler() with 16-bit datastreams,
-    introduced in version 1.0.2.
-  Revised makefile.macosx, makefile.dec, makefile.aix, and makefile.32sunu.
-
-Version 1.2.6beta2 [November 1, 2002]
-  Added libpng-config "--ldopts" output.
-  Added "AR=ar" and "ARFLAGS=rc" and changed "ar rc" to "$(AR) $(ARFLAGS)"
-    in makefiles.
-
-Version 1.2.6beta3 [July 18, 2004]
-  Reverted makefile changes from version 1.2.6beta2 and some of the changes
-    from version 1.2.6beta1; these will be postponed until version 1.2.7.
-    Version 1.2.6 is going to be a simple bugfix release.
-  Changed the one instance of "ln -sf" to "ln -f -s" in each Sun makefile.
-  Fixed potential overrun in pngerror.c by using strncpy instead of memcpy.
-  Added "#!/bin/sh" at the top of configure, for recognition of the
-    'x' flag under Cygwin (Cosmin).
-  Optimized vacuous tests that silence compiler warnings, in png.c (Cosmin).
-  Added support for PNG_USER_CONFIG, in pngconf.h (Cosmin).
-  Fixed the special memory handler for Borland C under DOS, in pngmem.c
-    (Cosmin).
-  Removed some spurious assignments in pngrutil.c (Cosmin).
-  Replaced 65536 with 65536L, and 0xffff with 0xffffL, to silence warnings
-    on 16-bit platforms (Cosmin).
-  Enclosed shift op expressions in parentheses, to silence warnings (Cosmin).
-  Used proper type png_fixed_point, to avoid problems on 16-bit platforms,
-    in png_handle_sRGB() (Cosmin).
-  Added compression_type to png_struct, and optimized the window size
-    inside the deflate stream (Cosmin).
-  Fixed definition of isnonalpha(), in pngerror.c and pngrutil.c (Cosmin).
-  Fixed handling of unknown chunks that come after IDAT (Cosmin).
-  Allowed png_error() and png_warning() to work even if png_ptr == NULL
-    (Cosmin).
-  Replaced row_info->rowbytes with row_bytes in png_write_find_filter()
-    (Cosmin).
-  Fixed definition of PNG_LIBPNG_VER_DLLNUM (Simon-Pierre).
-  Used PNG_LIBPNG_VER and PNG_LIBPNG_VER_STRING instead of the hardcoded
-    values in png.c (Simon-Pierre, Cosmin).
-  Initialized png_libpng_ver[] with PNG_LIBPNG_VER_STRING (Simon-Pierre).
-  Replaced PNG_LIBPNG_VER_MAJOR with PNG_LIBPNG_VER_DLLNUM in png.rc
-    (Simon-Pierre).
-  Moved the definition of PNG_HEADER_VERSION_STRING near the definitions
-    of the other PNG_LIBPNG_VER_... symbols in png.h (Cosmin).
-  Relocated #ifndef PNGAPI guards in pngconf.h (Simon-Pierre, Cosmin).
-  Updated scripts/makefile.vc(a)win32 (Cosmin).
-  Updated the MSVC project (Simon-Pierre, Cosmin).
-  Updated the Borland C++ Builder project (Cosmin).
-  Avoided access to asm_flags in pngvcrd.c, if PNG_1_0_X is defined (Cosmin).
-  Commented out warning about uninitialized mmx_support in pngvcrd.c (Cosmin).
-  Removed scripts/makefile.bd32 and scripts/pngdef.pas (Cosmin).
-  Added extra guard around inclusion of Turbo C memory headers, in pngconf.h
-    (Cosmin).
-  Renamed projects/msvc/ to projects/visualc6/, and projects/borland/ to
-    projects/cbuilder5/ (Cosmin).
-  Moved projects/visualc6/png32ms.def to scripts/pngw32.def,
-    and projects/visualc6/png.rc to scripts/pngw32.rc (Cosmin).
-  Added projects/visualc6/pngtest.dsp; removed contrib/msvctest/ (Cosmin).
-  Changed line endings to DOS style in cbuilder5 and visualc6 files, even
-    in the tar.* distributions (Cosmin).
-  Updated contrib/visupng/VisualPng.dsp (Cosmin).
-  Updated contrib/visupng/cexcept.h to version 2.0.0 (Cosmin).
-  Added a separate distribution with "configure" and supporting files (Junichi).
-
-Version 1.2.6beta4 [July 28, 2004]
-  Added user ability to change png_size_t via a PNG_SIZE_T macro.
-  Added png_sizeof() and png_convert_size() functions.
-  Added PNG_SIZE_MAX (maximum value of a png_size_t variable.
-  Added check in png_malloc_default() for (size_t)size != (png_uint_32)size
-    which would indicate an overflow.
-  Changed sPLT failure action from png_error to png_warning and abandon chunk.
-  Changed sCAL and iCCP failures from png_error to png_warning and abandon.
-  Added png_get_uint_31(png_ptr, buf) function.
-  Added PNG_UINT_32_MAX macro.
-  Renamed PNG_MAX_UINT to PNG_UINT_31_MAX.
-  Made png_zalloc() issue a png_warning and return NULL on potential
-    overflow.
-  Turn on PNG_NO_ZALLOC_ZERO by default in version 1.2.x
-  Revised "clobber list" in pnggccrd.c so it will compile under gcc-3.4.
-  Revised Borland portion of png_malloc() to return NULL or issue
-    png_error() according to setting of PNG_FLAG_MALLOC_NULL_MEM_OK.
-  Added PNG_NO_SEQUENTIAL_READ_SUPPORTED macro to conditionally remove
-    sequential read support.
-  Added some "#if PNG_WRITE_SUPPORTED" blocks.
-  Added #ifdef to remove some redundancy in png_malloc_default().
-  Use png_malloc instead of png_zalloc to allocate the pallete.
-
-Version 1.0.16rc1 and 1.2.6rc1 [August 4, 2004]
-  Fixed buffer overflow vulnerability (CVE-2004-0597) in png_handle_tRNS().
-  Fixed NULL dereference vulnerability (CVE-2004-0598) in png_handle_iCCP().
-  Fixed integer overflow vulnerability (CVE-2004-0599) in png_read_png().
-  Fixed some harmless bugs in png_handle_sBIT, etc, that would cause
-    duplicate chunk types to go undetected.
-  Fixed some timestamps in the -config version
-  Rearranged order of processing of color types in png_handle_tRNS().
-  Added ROWBYTES macro to calculate rowbytes without integer overflow.
-  Updated makefile.darwin and removed makefile.macosx from scripts directory.
-  Imposed default one million column, one-million row limits on the image
-    dimensions, and added png_set_user_limits() function to override them.
-  Revised use of PNG_SET_USER_LIMITS_SUPPORTED macro.
-  Fixed wrong cast of returns from png_get_user_width|height_max().
-  Changed some "keep the compiler happy" from empty statements to returns,
-  Revised libpng.txt to remove 1.2.x stuff from the 1.0.x distribution
-
-Version 1.0.16rc2 and 1.2.6rc2 [August 7, 2004]
-  Revised makefile.darwin and makefile.solaris.  Removed makefile.macosx.
-  Revised pngtest's png_debug_malloc() to use png_malloc() instead of
-    png_malloc_default() which is not supposed to be exported.
-  Fixed off-by-one error in one of the conversions to PNG_ROWBYTES() in
-    pngpread.c.  Bug was introduced in 1.2.6rc1.
-  Fixed bug in RGB to RGBX transformation introduced in 1.2.6rc1.
-  Fixed old bug in RGB to Gray transformation.
-  Fixed problem with 64-bit compilers by casting arguments to abs()
-    to png_int_32.
-  Changed "ln -sf" to "ln -f -s" in three makefiles (solaris, sco, so9).
-  Changed "HANDLE_CHUNK_*" to "PNG_HANDLE_CHUNK_*" (Cosmin)
-  Added "-@/bin/rm -f $(DL)/$(LIBNAME).so.$(PNGMAJ)" to 15 *NIX makefiles.
-  Added code to update the row_info->colortype in png_do_read_filler() (MSB).
-
-Version 1.0.16rc3 and 1.2.6rc3 [August 9, 2004]
-  Eliminated use of "abs()" in testing cHRM and gAMA values, to avoid
-    trouble with some 64-bit compilers.  Created PNG_OUT_OF_RANGE() macro.
-  Revised documentation of png_set_keep_unknown_chunks().
-  Check handle_as_unknown status in pngpread.c, as in pngread.c previously.
-  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_INTERNAL section of png.h
-  Added "rim" definitions for CONST4 and CONST6 in pnggccrd.c
-
-Version 1.0.16rc4 and 1.2.6rc4 [August 10, 2004]
-  Fixed mistake in pngtest.c introduced in 1.2.6rc2 (declaration of
-    "pinfo" was out of place).
-
-Version 1.0.16rc5 and 1.2.6rc5 [August 10, 2004]
-  Moved  "PNG_HANDLE_CHUNK_*" macros out of PNG_ASSEMBLER_CODE_SUPPORTED
-    section of png.h where they were inadvertently placed in version rc3.
-
-Version 1.2.6 and 1.0.16 [August 15, 2004]
-  Revised pngtest so memory allocation testing is only done when PNG_DEBUG==1.
-
-Version 1.2.7beta1 [August 26, 2004]
-  Removed unused pngasmrd.h file.
-  Removed references to uu.net for archived files.  Added references to
-    PNG Spec (second edition) and the PNG ISO/IEC Standard.
-  Added "test-dd" target in 15 makefiles, to run pngtest in DESTDIR.
-  Fixed bug with "optimized window size" in the IDAT datastream, that
-    causes libpng to write PNG files with incorrect zlib header bytes.
-
-Version 1.2.7beta2 [August 28, 2004]
-  Fixed bug with sCAL chunk and big-endian machines (David Munro).
-  Undid new code added in 1.2.6rc2 to update the color_type in
-    png_set_filler().
-  Added png_set_add_alpha() that updates color type.
-
-Version 1.0.17rc1 and 1.2.7rc1 [September 4, 2004]
-  Revised png_set_strip_filler() to not remove alpha if color_type has alpha.
-
-Version 1.2.7 and 1.0.17 [September 12, 2004]
-  Added makefile.hp64
-  Changed projects/msvc/png32ms.def to scripts/png32ms.def in makefile.cygwin
-
-Version 1.2.8beta1 [November 1, 2004]
-  Fixed bug in png_text_compress() that would fail to complete a large block.
-  Fixed bug, introduced in libpng-1.2.7, that overruns a buffer during
-    strip alpha operation in png_do_strip_filler().
-  Added PNG_1_2_X definition in pngconf.h
-  Use #ifdef to comment out png_info_init in png.c and png_read_init in
-    pngread.c (as of 1.3.0)
-
-Version 1.2.8beta2 [November 2, 2004]
-  Reduce color_type to a nonalpha type after strip alpha operation in
-    png_do_strip_filler().
-
-Version 1.2.8beta3 [November 3, 2004]
-  Revised definitions of PNG_MAX_UINT_32, PNG_MAX_SIZE, and PNG_MAXSUM
-
-Version 1.2.8beta4 [November 12, 2004]
-  Fixed (again) definition of PNG_LIBPNG_VER_DLLNUM in png.h (Cosmin).
-  Added PNG_LIBPNG_BUILD_PRIVATE in png.h (Cosmin).
-  Set png_ptr->zstream.data_type to Z_BINARY, to avoid unnecessary detection
-    of data type in deflate (Cosmin).
-  Deprecated but continue to support SPECIALBUILD and PRIVATEBUILD in favor of
-    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
-
-Version 1.2.8beta5 [November 20, 2004]
-  Use png_ptr->flags instead of png_ptr->transformations to pass
-    PNG_STRIP_ALPHA info to png_do_strip_filler(), to preserve ABI
-    compatibility.
-  Revised handling of SPECIALBUILD, PRIVATEBUILD,
-    PNG_LIBPNG_BUILD_SPECIAL_STRING and PNG_LIBPNG_BUILD_PRIVATE_STRING.
-
-Version 1.2.8rc1 [November 24, 2004]
-  Moved handling of BUILD macros from pngconf.h to png.h
-  Added definition of PNG_LIBPNG_BASE_TYPE in png.h, inadvertently
-    omitted from beta5.
-  Revised scripts/pngw32.rc
-  Despammed mailing addresses by masking "@" with "at".
-  Inadvertently installed a supposedly faster test version of pngrutil.c
-
-Version 1.2.8rc2 [November 26, 2004]
-  Added two missing "\" in png.h
-  Change tests in pngread.c and pngpread.c to
-    if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
-       png_do_read_transformations(png_ptr);
-
-Version 1.2.8rc3 [November 28, 2004]
-  Reverted pngrutil.c to version libpng-1.2.8beta5.
-  Added scripts/makefile.elf with supporting code in pngconf.h for symbol
-    versioning (John Bowler).
-
-Version 1.2.8rc4 [November 29, 2004]
-  Added projects/visualc7 (Simon-pierre).
-
-Version 1.2.8rc5 [November 29, 2004]
-  Fixed new typo in scripts/pngw32.rc
-
-Version 1.2.8 [December 3, 2004]
-  Removed projects/visualc7, added projects/visualc71.
-
-Version 1.2.9beta1 [February 21, 2006]
-  Initialized some structure members in pngwutil.c to avoid gcc-4.0.0 complaints
-  Revised man page and libpng.txt to make it clear that one should not call
-    png_read_end or png_write_end after png_read_png or png_write_png.
-  Updated references to png-mng-implement mailing list.
-  Fixed an incorrect typecast in pngrutil.c
-  Added PNG_NO_READ_SUPPORTED conditional for making a write-only library.
-  Added PNG_NO_WRITE_INTERLACING_SUPPORTED conditional.
-  Optimized alpha-inversion loops in pngwtran.c
-  Moved test for nonzero gamma outside of png_build_gamma_table() in pngrtran.c
-  Make sure num_trans is <= 256 before copying data in png_set_tRNS().
-  Make sure num_palette is <= 256 before copying data in png_set_PLTE().
-  Interchanged order of write_swap_alpha and write_invert_alpha transforms.
-  Added parentheses in the definition of PNG_LIBPNG_BUILD_TYPE (Cosmin).
-  Optimized zlib window flag (CINFO) in contrib/pngsuite/*.png (Cosmin).
-  Updated scripts/makefile.bc32 for Borland C++ 5.6 (Cosmin).
-  Exported png_get_uint_32, png_save_uint_32, png_get_uint_16, png_save_uint_16,
-    png_get_int_32, png_save_int_32, png_get_uint_31 (Cosmin).
-  Added type cast (png_byte) in png_write_sCAL() (Cosmin).
-  Fixed scripts/makefile.cygwin (Christian Biesinger, Cosmin).
-  Default iTXt support was inadvertently enabled.
-
-Version 1.2.9beta2 [February 21, 2006]
-  Check for png_rgb_to_gray and png_gray_to_rgb read transformations before
-    checking for png_read_dither in pngrtran.c
-  Revised checking of chromaticity limits to accommodate extended RGB
-    colorspace (John Denker).
-  Changed line endings in some of the project files to CRLF, even in the
-    "Unix" tar distributions (Cosmin).
-  Made png_get_int_32 and png_save_int_32 always available (Cosmin).
-  Updated scripts/pngos2.def, scripts/pngw32.def and projects/wince/png32ce.def
-    with the newly exported functions.
-  Eliminated distributions without the "configure" script.
-  Updated INSTALL instructions.
-
-Version 1.2.9beta3 [February 24, 2006]
-  Fixed CRCRLF line endings in contrib/visupng/VisualPng.dsp
-  Made libpng.pc respect EXEC_PREFIX (D. P. Kreil, J. Bowler)
-  Removed reference to pngasmrd.h from Makefile.am
-  Renamed CHANGES to ChangeLog.
-  Renamed LICENSE to COPYING.
-  Renamed ANNOUNCE to NEWS.
-  Created AUTHORS file.
-
-Version 1.2.9beta4 [March 3, 2006]
-  Changed definition of PKGCONFIG from $prefix/lib to $libdir in configure.ac
-  Reverted to filenames LICENSE and ANNOUNCE; removed AUTHORS and COPYING.
-  Removed newline from the end of some error and warning messages.
-  Removed test for sqrt() from configure.ac and configure.
-  Made swap tables in pngtrans.c PNG_CONST (Carlo Bramix).
-  Disabled default iTXt support that was inadvertently enabled in
-    libpng-1.2.9beta1.
-  Added "OS2" to list of systems that don't need underscores, in pnggccrd.c
-  Removed libpng version and date from *.c files.
-
-Version 1.2.9beta5 [March 4, 2006]
-  Removed trailing blanks from source files.
-  Put version and date of latest change in each source file, and changed
-    copyright year accordingly.
-  More cleanup of configure.ac, Makefile.am, and associated scripts.
-  Restored scripts/makefile.elf which was inadvertently deleted.
-
-Version 1.2.9beta6 [March 6, 2006]
-  Fixed typo (RELEASE) in configuration files.
-
-Version 1.2.9beta7 [March 7, 2006]
-  Removed libpng.vers and libpng.sym from libpng12_la_SOURCES in Makefile.am
-  Fixed inconsistent #ifdef's around png_sig_bytes() and png_set_sCAL_s()
-    in png.h.
-  Updated makefile.elf as suggested by debian.
-  Made cosmetic changes to some makefiles, adding LN_SF and other macros.
-  Made some makefiles accept "exec_prefix".
-
-Version 1.2.9beta8 [March 9, 2006]
-  Fixed some "#if defined (..." which should be "#if defined(..."
-    Bug introduced in libpng-1.2.8.
-  Fixed inconsistency in definition of png_default_read_data()
-  Restored blank that was lost from makefile.sggcc "clean" target in beta7.
-  Revised calculation of "current" and "major" for irix in ltmain.sh
-  Changed "mkdir" to "MKDIR_P" in some makefiles.
-  Separated PNG_EXPAND and PNG_EXPAND_tRNS.
-  Added png_set_expand_gray_1_2_4_to_8() and deprecated
-    png_set_gray_1_2_4_to_8() which also expands tRNS to alpha.
-
-Version 1.2.9beta9 [March 10, 2006]
-  Include "config.h" in pngconf.h when available.
-  Added some checks for NULL png_ptr or NULL info_ptr (timeless)
-
-Version 1.2.9beta10 [March 20, 2006]
-  Removed extra CR from contrib/visualpng/VisualPng.dsw (Cosmin)
-  Made pnggccrd.c PIC-compliant (Christian Aichinger).
-  Added makefile.mingw (Wolfgang Glas).
-  Revised pngconf.h MMX checking.
-
-Version 1.2.9beta11 [March 22, 2006]
-  Fixed out-of-order declaration in pngwrite.c that was introduced in beta9
-  Simplified some makefiles by using LIBSO, LIBSOMAJ, and LIBSOVER macros.
-
-Version 1.2.9rc1 [March 31, 2006]
-  Defined PNG_USER_PRIVATEBUILD when including "pngusr.h" (Cosmin).
-  Removed nonsensical assertion check from pngtest.c (Cosmin).
-
-Version 1.2.9 [April 14, 2006]
-  Revised makefile.beos and added "none" selector in ltmain.sh
-
-Version 1.2.10beta1 [April 15, 2006]
-  Renamed "config.h" to "png_conf.h" and revised Makefile.am to add
-    -DPNG_BUILDING_LIBPNG to compile directive, and modified pngconf.h
-    to include png_conf.h only when PNG_BUILDING_LIBPNG is defined.
-
-Version 1.2.10beta2 [April 15, 2006]
-  Manually updated Makefile.in and configure.  Changed png_conf.h.in
-    back to config.h.
-
-Version 1.2.10beta3 [April 15, 2006]
-  Change png_conf.h back to config.h in pngconf.h.
-
-Version 1.2.10beta4 [April 16, 2006]
-  Change PNG_BUILDING_LIBPNG to PNG_CONFIGURE_LIBPNG in config/Makefile*.
-
-Version 1.2.10beta5 [April 16, 2006]
-  Added a configure check for compiling assembler code in pnggccrd.c
-
-Version 1.2.10beta6 [April 17, 2006]
-  Revised the configure check for pnggccrd.c
-  Moved -DPNG_CONFIGURE_LIBPNG into @LIBPNG_DEFINES@
-  Added @LIBPNG_DEFINES@ to arguments when building libpng.sym
-
-Version 1.2.10beta7 [April 18, 2006]
-  Change "exec_prefix=$prefix" to "exec_prefix=$(prefix)" in makefiles.
-
-Version 1.2.10rc1 [April 19, 2006]
-  Ensure pngconf.h doesn't define both PNG_USE_PNGGCCRD and PNG_USE_PNGVCRD
-  Fixed "LN_FS" typo in makefile.sco and makefile.solaris.
-
-Version 1.2.10rc2 [April 20, 2006]
-  Added a backslash between -DPNG_CONFIGURE_LIBPNG and -DPNG_NO_ASSEMBLER_CODE
-   in configure.ac and configure
-  Made the configure warning about versioned symbols less arrogant.
-
-Version 1.2.10rc3 [April 21, 2006]
-  Added a note in libpng.txt that png_set_sig_bytes(8) can be used when
-    writing an embedded PNG without the 8-byte signature.
-  Revised makefiles and configure to avoid making links to libpng.so.*
-
-Version 1.2.10 [April 23, 2006]
-  Reverted configure to "rc2" state.
-
-Version 1.2.11beta1 [May 31, 2006]
-  scripts/libpng.pc.in contained "configure" style version info and would
-    not work with makefiles.
-  The shared-library makefiles were linking to libpng.so.0 instead of
-    libpng.so.3 compatibility as the library.
-
-Version 1.2.11beta2 [June 2, 2006]
-  Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
-    buffer overflow.
-  Fixed bug in example.c (png_set_palette_rgb -> png_set_palette_to_rgb)
-
-Version 1.2.11beta3 [June 5, 2006]
-  Prepended "#! /bin/sh" to ltmail.sh and contrib/pngminus/*.sh (Cosmin).
-  Removed the accidental leftover Makefile.in~ (Cosmin).
-  Avoided potential buffer overflow and optimized buffer in
-    png_write_sCAL(), png_write_sCAL_s() (Cosmin).
-  Removed the include directories and libraries from CFLAGS and LDFLAGS
-    in scripts/makefile.gcc (Nelson A. de Oliveira, Cosmin).
-
-Version 1.2.11beta4 [June 6, 2006]
-  Allow zero-length IDAT chunks after the entire zlib datastream, but not
-    after another intervening chunk type.
-
-Version 1.0.19rc1, 1.2.11rc1 [June 13, 2006]
-  Deleted extraneous square brackets from [config.h] in configure.ac
-
-Version 1.0.19rc2, 1.2.11rc2 [June 14, 2006]
-  Added prototypes for PNG_INCH_CONVERSIONS functions to png.h
-  Revised INSTALL and autogen.sh
-  Fixed typo in several makefiles (-W1 should be -Wl)
-  Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
-
-Version 1.0.19rc3, 1.2.11rc3 [June 15, 2006]
-  Removed the new typedefs for 64-bit systems (delay until version 1.4.0)
-  Added one zero element to png_gamma_shift[] array in pngrtran.c to avoid
-    reading out of bounds.
-
-Version 1.0.19rc4, 1.2.11rc4 [June 15, 2006]
-  Really removed the new typedefs for 64-bit systems.
-
-Version 1.0.19rc5, 1.2.11rc5 [June 22, 2006]
-  Removed png_sig_bytes entry from scripts/pngw32.def
-
-Version 1.0.19, 1.2.11 [June 26, 2006]
-  None.
-
-Version 1.0.20, 1.2.12 [June 27, 2006]
-  Really increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
-    buffer overflow.
-
-Version 1.2.13beta1 [October 2, 2006]
-  Removed AC_FUNC_MALLOC from configure.ac
-  Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
-  Change "logical" to "bitwise" throughout documentation.
-  Detect and fix attempt to write wrong iCCP profile length (CVE-2006-7244)
-
-Version 1.0.21, 1.2.13 [November 14, 2006]
-  Fix potential buffer overflow in sPLT chunk handler.
-  Fix Makefile.am to not try to link to noexistent files.
-  Check all exported functions for NULL png_ptr.
-
-Version 1.2.14beta1 [November 17, 2006]
-  Relocated three misplaced tests for NULL png_ptr.
-  Built Makefile.in with automake-1.9.6 instead of 1.9.2.
-  Build configure with autoconf-2.60 instead of 2.59
-
-Version 1.2.14beta2 [November 17, 2006]
-  Added some typecasts in png_zalloc().
-
-Version 1.2.14rc1 [November 20, 2006]
-  Changed "strtod" to "png_strtod" in pngrutil.c
-
-Version 1.0.22, 1.2.14    [November 27, 2006]
-  Added missing "$(srcdir)" in Makefile.am and Makefile.in
-
-Version 1.2.15beta1 [December 3, 2006]
-  Generated configure with autoconf-2.61 instead of 2.60
-  Revised configure.ac to update libpng.pc and libpng-config.
-
-Version 1.2.15beta2 [December 3, 2006]
-  Always export MMX asm functions, just stubs if not building pnggccrd.c
-
-Version 1.2.15beta3 [December 4, 2006]
-  Add "png_bytep" typecast to profile while calculating length in pngwutil.c
-
-Version 1.2.15beta4 [December 7, 2006]
-  Added scripts/CMakeLists.txt
-  Changed PNG_NO_ASSEMBLER_CODE to PNG_NO_MMX_CODE in scripts, like 1.4.0beta
-
-Version 1.2.15beta5 [December 7, 2006]
-  Changed some instances of PNG_ASSEMBLER_* to PNG_MMX_* in pnggccrd.c
-  Revised scripts/CMakeLists.txt
-
-Version 1.2.15beta6 [December 13, 2006]
-  Revised scripts/CMakeLists.txt and configure.ac
-
-Version 1.2.15rc1 [December 18, 2006]
-  Revised scripts/CMakeLists.txt
-
-Version 1.2.15rc2 [December 21, 2006]
-  Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
-  Added scripts/makefile.nommx
-
-Version 1.2.15rc3 [December 25, 2006]
-  Fixed shared library numbering error that was introduced in 1.2.15beta6.
-
-Version 1.2.15rc4 [December 27, 2006]
-  Fixed handling of rgb_to_gray when png_ptr->color.gray isn't set.
-
-Version 1.2.15rc5 [December 31, 2006]
-  Revised handling of rgb_to_gray.
-
-Version 1.2.15 [January 5, 2007]
-  Added some (unsigned long) typecasts in pngtest.c to avoid printing errors.
-
-Version 1.2.16beta1 [January 6, 2007]
-  Fix bugs in makefile.nommx
-
-Version 1.2.16beta2 [January 16, 2007]
-  Revised scripts/CMakeLists.txt
-
-Version 1.2.16 [January 31, 2007]
-  No changes.
-
-Version 1.2.17beta1 [March 6, 2007]
-  Revised scripts/CMakeLists.txt to install both shared and static libraries.
-  Deleted a redundant line from pngset.c.
-
-Version 1.2.17beta2 [April 26, 2007]
-  Relocated misplaced test for png_ptr == NULL in pngpread.c
-  Change "==" to "&" for testing PNG_RGB_TO_GRAY_ERR & PNG_RGB_TO_GRAY_WARN
-    flags.
-  Changed remaining instances of PNG_ASSEMBLER_* to PNG_MMX_*
-  Added pngerror() when write_IHDR fails in deflateInit2().
-  Added "const" to some array declarations.
-  Mention examples of libpng usage in the libpng*.txt and libpng.3 documents.
-
-Version 1.2.17rc1 [May 4, 2007]
-  No changes.
-
-Version 1.2.17rc2 [May 8, 2007]
-  Moved several PNG_HAVE_* macros out of PNG_INTERNAL because applications
-    calling set_unknown_chunk_location() need them.
-  Changed transformation flag from PNG_EXPAND_tRNS to PNG_EXPAND in
-    png_set_expand_gray_1_2_4_to_8().
-  Added png_ptr->unknown_chunk to hold working unknown chunk data, so it
-    can be free'ed in case of error.  Revised unknown chunk handling in
-    pngrutil.c and pngpread.c to use this structure.
-
-Version 1.2.17rc3 [May 8, 2007]
-  Revised symbol-handling in configure script.
-
-Version 1.2.17rc4 [May 10, 2007]
-  Revised unknown chunk handling to avoid storing unknown critical chunks.
-
-Version 1.0.25 [May 15, 2007]
-Version 1.2.17 [May 15, 2007]
-  Added "png_ptr->num_trans=0" before error return in png_handle_tRNS,
-    to eliminate a vulnerability (CVE-2007-2445, CERT VU#684664)
-
-Version 1.0.26 [May 15, 2007]
-Version 1.2.18 [May 15, 2007]
-  Reverted the libpng-1.2.17rc3 change to symbol-handling in configure script
-
-Version 1.2.19beta1 [May 18, 2007]
-  Changed "const static" to "static PNG_CONST" everywhere, mostly undoing
-    change of libpng-1.2.17beta2.  Changed other "const" to "PNG_CONST"
-  Changed some handling of unused parameters, to avoid compiler warnings.
-    "if (unused == NULL) return;" becomes "unused = unused".
-
-Version 1.2.19beta2 [May 18, 2007]
-  Only use the valid bits of tRNS value in png_do_expand() (Brian Cartier)
-
-Version 1.2.19beta3 [May 19, 2007]
-  Add some "png_byte" typecasts in png_check_keyword() and write new_key
-  instead of key in zTXt chunk (Kevin Ryde).
-
-Version 1.2.19beta4 [May 21, 2007]
-  Add png_snprintf() function and use it in place of sprint() for improved
-    defense against buffer overflows.
-
-Version 1.2.19beta5 [May 21, 2007]
-  Fixed png_handle_tRNS() to only use the valid bits of tRNS value.
-  Changed handling of more unused parameters, to avoid compiler warnings.
-  Removed some PNG_CONST in pngwutil.c to avoid compiler warnings.
-
-Version 1.2.19beta6 [May 22, 2007]
-  Added some #ifdef PNG_MMX_CODE_SUPPORTED where needed in pngvcrd.c
-  Added a special "_MSC_VER" case that defines png_snprintf to _snprintf
-
-Version 1.2.19beta7 [May 22, 2007]
-  Squelched png_squelch_warnings() in pnggccrd.c and added
-    an #ifdef PNG_MMX_CODE_SUPPORTED block around the declarations that caused
-    the warnings that png_squelch_warnings was squelching.
-
-Version 1.2.19beta8 [May 22, 2007]
-  Removed __MMX__ from test in pngconf.h.
-
-Version 1.2.19beta9 [May 23, 2007]
-  Made png_squelch_warnings() available via PNG_SQUELCH_WARNINGS macro.
-  Revised png_squelch_warnings() so it might work.
-  Updated makefile.sgcc and makefile.solaris; added makefile.solaris-x86.
-
-Version 1.2.19beta10 [May 24, 2007]
-  Resquelched png_squelch_warnings(), use "__attribute__((used))" instead.
-
-Version 1.4.0beta1 [April 20, 2006]
-  Enabled iTXt support (changes png_struct, thus requires so-number change).
-  Cleaned up PNG_ASSEMBLER_CODE_SUPPORTED vs PNG_MMX_CODE_SUPPORTED
-  Eliminated PNG_1_0_X and PNG_1_2_X macros.
-  Removed deprecated functions png_read_init, png_write_init, png_info_init,
-    png_permit_empty_plte, png_set_gray_1_2_4_to_8, png_check_sig, and
-    removed the deprecated macro PNG_MAX_UINT.
-  Moved "PNG_INTERNAL" parts of png.h and pngconf.h into pngintrn.h
-  Removed many WIN32_WCE #ifdefs (Cosmin).
-  Reduced dependency on C-runtime library when on Windows (Simon-Pierre)
-  Replaced sprintf() with png_sprintf() (Simon-Pierre)
-
-Version 1.4.0beta2 [April 20, 2006]
-  Revised makefiles and configure to avoid making links to libpng.so.*
-  Moved some leftover MMX-related defines from pngconf.h to pngintrn.h
-  Updated scripts/pngos2.def, pngw32.def, and projects/wince/png32ce.def
-
-Version 1.4.0beta3 [May 10, 2006]
-  Updated scripts/pngw32.def to comment out MMX functions.
-  Added PNG_NO_GET_INT_32 and PNG_NO_SAVE_INT_32 macros.
-  Scripts/libpng.pc.in contained "configure" style version info and would
-    not work with makefiles.
-  Revised pngconf.h and added pngconf.h.in, so makefiles and configure can
-    pass defines to libpng and applications.
-
-Version 1.4.0beta4 [May 11, 2006]
-  Revised configure.ac, Makefile.am, and many of the makefiles to write
-    their defines in pngconf.h.
-
-Version 1.4.0beta5 [May 15, 2006]
-  Added a missing semicolon in Makefile.am and Makefile.in
-  Deleted extraneous square brackets from configure.ac
-
-Version 1.4.0beta6 [June 2, 2006]
-  Increased sprintf buffer from 50 to 52 chars in pngrutil.c to avoid
-    buffer overflow.
-  Changed sonum from 0 to 1.
-  Removed unused prototype for png_check_sig() from png.h
-
-Version 1.4.0beta7 [June 16, 2006]
-  Exported png_write_sig (Cosmin).
-  Optimized buffer in png_handle_cHRM() (Cosmin).
-  Set pHYs = 2835 x 2835 pixels per meter, and added
-    sCAL = 0.352778e-3 x 0.352778e-3 meters, in pngtest.png (Cosmin).
-  Added png_set_benign_errors(), png_benign_error(), png_chunk_benign_error().
-  Added typedef for png_int_32 and png_uint_32 on 64-bit systems.
-  Added "(unsigned long)" typecast on png_uint_32 variables in printf lists.
-
-Version 1.4.0beta8 [June 22, 2006]
-  Added demonstration of user chunk support in pngtest.c, to support the
-    public sTER chunk and a private vpAg chunk.
-
-Version 1.4.0beta9 [July 3, 2006]
-  Removed ordinals from scripts/pngw32.def and removed png_info_int and
-    png_set_gray_1_2_4_to_8 entries.
-  Inline call of png_get_uint_32() in png_get_uint_31().
-  Use png_get_uint_31() to get vpAg width and height in pngtest.c
-  Removed WINCE and Netware projects.
-  Removed standalone Y2KINFO file.
-
-Version 1.4.0beta10 [July 12, 2006]
-  Eliminated automatic copy of pngconf.h to pngconf.h.in from configure and
-    some makefiles, because it was not working reliably.  Instead, distribute
-    pngconf.h.in along with pngconf.h and cause configure and some of the
-    makefiles to update pngconf.h from pngconf.h.in.
-  Added pngconf.h to DEPENDENCIES in Makefile.am
-
-Version 1.4.0beta11 [August 19, 2006]
-  Removed AC_FUNC_MALLOC from configure.ac.
-  Added a warning when writing iCCP profile with mismatched profile length.
-  Patched pnggccrd.c to assemble on x86_64 platforms.
-  Moved chunk header reading into a separate function png_read_chunk_header()
-    in pngrutil.c.  The chunk header (len+sig) is now serialized in a single
-    operation (Cosmin).
-  Implemented support for I/O states. Added png_ptr member io_state, and
-    functions png_get_io_chunk_name() and png_get_io_state() in pngget.c
-    (Cosmin).
-  Added png_get_io_chunk_name and png_get_io_state to scripts/*.def (Cosmin).
-  Renamed scripts/pngw32.* to scripts/pngwin.* (Cosmin).
-  Removed the include directories and libraries from CFLAGS and LDFLAGS
-    in scripts/makefile.gcc (Cosmin).
-  Used png_save_uint_32() to set vpAg width and height in pngtest.c (Cosmin).
-  Cast to proper type when getting/setting vpAg units in pngtest.c (Cosmin).
-  Added pngintrn.h to the Visual C++ projects (Cosmin).
-  Removed scripts/list (Cosmin).
-  Updated copyright year in scripts/pngwin.def (Cosmin).
-  Removed PNG_TYPECAST_NULL and used standard NULL consistently (Cosmin).
-  Disallowed the user to redefine png_size_t, and enforced a consistent use
-    of png_size_t across libpng (Cosmin).
-  Changed the type of png_ptr->rowbytes, PNG_ROWBYTES() and friends
-    to png_size_t (Cosmin).
-  Removed png_convert_size() and replaced png_sizeof with sizeof (Cosmin).
-  Removed some unnecessary type casts (Cosmin).
-  Changed prototype of png_get_compression_buffer_size() and
-    png_set_compression_buffer_size() to work with png_size_t instead of
-    png_uint_32 (Cosmin).
-  Removed png_memcpy_check() and png_memset_check() (Cosmin).
-  Fixed a typo (png_byte --> png_bytep) in libpng.3 and libpng.txt (Cosmin).
-  Clarified that png_zalloc() does not clear the allocated memory,
-    and png_zalloc() and png_zfree() cannot be PNGAPI (Cosmin).
-  Renamed png_mem_size_t to png_alloc_size_t, fixed its definition in
-    pngconf.h, and used it in all memory allocation functions (Cosmin).
-  Renamed pngintrn.h to pngpriv.h, added a comment at the top of the file
-    mentioning that the symbols declared in that file are private, and
-    updated the scripts and the Visual C++ projects accordingly (Cosmin).
-  Removed circular references between pngconf.h and pngconf.h.in in
-    scripts/makefile.vc*win32 (Cosmin).
-  Removing trailing '.' from the warning and error messages (Cosmin).
-  Added pngdefs.h that is built by makefile or configure, instead of
-    pngconf.h.in (Glenn).
-  Detect and fix attempt to write wrong iCCP profile length.
-
-Version 1.4.0beta12 [October 19, 2006]
-  Changed "logical" to "bitwise" in the documentation.
-  Work around Intel-Mac compiler bug by setting PNG_NO_MMX_CODE in pngconf.h
-  Add a typecast to stifle compiler warning in pngrutil.c
-
-Version 1.4.0beta13 [November 10, 2006]
-  Fix potential buffer overflow in sPLT chunk handler.
-  Fix Makefile.am to not try to link to noexistent files.
-
-Version 1.4.0beta14 [November 15, 2006]
-  Check all exported functions for NULL png_ptr.
-
-Version 1.4.0beta15 [November 17, 2006]
-  Relocated two misplaced tests for NULL png_ptr.
-  Built Makefile.in with automake-1.9.6 instead of 1.9.2.
-  Build configure with autoconf-2.60 instead of 2.59
-  Add "install: all" in Makefile.am so "configure; make install" will work.
-
-Version 1.4.0beta16 [November 17, 2006]
-  Added a typecast in png_zalloc().
-
-Version 1.4.0beta17 [December 4, 2006]
-  Changed "new_key[79] = '\0';" to "(*new_key)[79] = '\0';" in pngwutil.c
-  Add "png_bytep" typecast to profile while calculating length in pngwutil.c
-
-Version 1.4.0beta18 [December 7, 2006]
-  Added scripts/CMakeLists.txt
-
-Version 1.4.0beta19 [May 16, 2007]
-  Revised scripts/CMakeLists.txt
-  Rebuilt configure and Makefile.in with newer tools.
-  Added conditional #undef jmpbuf in pngtest.c to undo #define in AIX headers.
-  Added scripts/makefile.nommx
-
-Version 1.4.0beta20 [July 9, 2008]
-  Moved several PNG_HAVE_* macros from pngpriv.h to png.h because applications
-    calling set_unknown_chunk_location() need them.
-  Moved several macro definitions from pngpriv.h to pngconf.h
-  Merge with changes to the 1.2.X branch, as of 1.2.30beta04.
-  Deleted all use of the MMX assembler code and Intel-licensed optimizations.
-  Revised makefile.mingw
-
-Version 1.4.0beta21 [July 21, 2008]
-  Moved local array "chunkdata" from pngrutil.c to the png_struct, so
-    it will be freed by png_read_destroy() in case of a read error (Kurt
-    Christensen).
-
-Version 1.4.0beta22 [July 21, 2008]
-  Change "purpose" and "buffer" to png_ptr->chunkdata to avoid memory leaking.
-
-Version 1.4.0beta23 [July 22, 2008]
-  Change "chunkdata = NULL" to "png_ptr->chunkdata = NULL" several places in
-    png_decompress_chunk().
-
-Version 1.4.0beta24 [July 25, 2008]
-  Change all remaining "chunkdata" to "png_ptr->chunkdata" in
-    png_decompress_chunk(), and remove "chunkdata" from parameter list.
-  Put a call to png_check_chunk_name() in png_read_chunk_header().
-  Revised png_check_chunk_name() to reject a name with a lowercase 3rd byte.
-  Removed two calls to png_check_chunk_name() occurring later in the process.
-  Define PNG_NO_ERROR_NUMBERS by default in pngconf.h
-
-Version 1.4.0beta25 [July 30, 2008]
-  Added a call to png_check_chunk_name() in pngpread.c
-  Reverted png_check_chunk_name() to accept a name with a lowercase 3rd byte.
-  Added png_push_have_buffer() function to pngpread.c
-  Eliminated PNG_BIG_ENDIAN_SUPPORTED and associated png_get_* macros.
-  Made inline expansion of png_get_*() optional with PNG_USE_READ_MACROS.
-  Eliminated all PNG_USELESS_TESTS and PNG_CORRECT_PALETTE_SUPPORTED code.
-  Synced contrib directory and configure files with libpng-1.2.30beta06.
-  Eliminated no-longer-used pngdefs.h (but it's still built in the makefiles)
-  Relocated a misplaced "#endif /* PNG_NO_WRITE_FILTER */" in pngwutil.c
-
-Version 1.4.0beta26 [August 4, 2008]
-  Removed png_push_have_buffer() function in pngpread.c.  It increased the
-    compiled library size slightly.
-  Changed "-Wall" to "-W -Wall" in the CFLAGS in all makefiles (Cosmin Truta)
-  Declared png_ptr "volatile" in pngread.c and pngwrite.c to avoid warnings.
-  Updated contrib/visupng/cexcept.h to version 2.0.1
-  Added PNG_LITERAL_CHARACTER macros for #, [, and ].
-
-Version 1.4.0beta27 [August 5, 2008]
-  Revised usage of PNG_LITERAL_SHARP in pngerror.c.
-  Moved newline character from individual png_debug messages into the
-    png_debug macros.
-  Allow user to #define their own png_debug, png_debug1, and png_debug2.
-
-Version 1.4.0beta28 [August 5, 2008]
-  Revised usage of PNG_LITERAL_SHARP in pngerror.c.
-  Added PNG_STRING_NEWLINE macro
-
-Version 1.4.0beta29 [August 9, 2008]
-  Revised usage of PNG_STRING_NEWLINE to work on non-ISO compilers.
-  Added PNG_STRING_COPYRIGHT macro.
-  Added non-ISO versions of png_debug macros.
-
-Version 1.4.0beta30 [August 14, 2008]
-  Added premultiplied alpha feature (Volker Wiendl).
-
-Version 1.4.0beta31 [August 18, 2008]
-  Moved png_set_premultiply_alpha from pngtrans.c to pngrtran.c
-  Removed extra crc check at the end of png_handle_cHRM().  Bug introduced
-    in libpng-1.4.0beta20.
-
-Version 1.4.0beta32 [August 19, 2008]
-  Added PNG_WRITE_FLUSH_SUPPORTED block around new png_flush() call.
-  Revised PNG_NO_STDIO version of png_write_flush()
-
-Version 1.4.0beta33 [August 20, 2008]
-  Added png_get|set_chunk_cache_max() to limit the total number of sPLT,
-    text, and unknown chunks that can be stored.
-
-Version 1.4.0beta34 [September 6, 2008]
-  Shortened tIME_string to 29 bytes in pngtest.c
-  Fixed off-by-one error introduced in png_push_read_zTXt() function in
-    libpng-1.2.30beta04/pngpread.c (Harald van Dijk)
-
-Version 1.4.0beta35 [October 6, 2008]
-  Changed "trans_values" to "trans_color".
-  Changed so-number from 0 to 14.  Some OS do not like 0.
-  Revised makefile.darwin to fix shared library numbering.
-  Change png_set_gray_1_2_4_to_8() to png_set_expand_gray_1_2_4_to_8()
-    in example.c (debian bug report)
-
-Version 1.4.0beta36 [October 25, 2008]
-  Sync with tEXt vulnerability fix in libpng-1.2.33rc02.
-
-Version 1.4.0beta37 [November 13, 2008]
-  Added png_check_cHRM in png.c and moved checking from pngget.c, pngrutil.c,
-    and pngwrite.c
-
-Version 1.4.0beta38 [November 22, 2008]
-  Added check for zero-area RGB cHRM triangle in png_check_cHRM() and
-    png_check_cHRM_fixed().
-
-Version 1.4.0beta39 [November 23, 2008]
-  Revised png_warning() to write its message on standard output by default
-    when warning_fn is NULL.
-
-Version 1.4.0beta40 [November 24, 2008]
-  Eliminated png_check_cHRM().  Instead, always use png_check_cHRM_fixed().
-  In png_check_cHRM_fixed(), ensure white_y is > 0, and removed redundant
-    check for all-zero coordinates that is detected by the triangle check.
-
-Version 1.4.0beta41 [November 26, 2008]
-  Fixed string vs pointer-to-string error in png_check_keyword().
-  Rearranged test expressions in png_check_cHRM_fixed() to avoid internal
-    overflows.
-  Added PNG_NO_CHECK_cHRM conditional.
-
-Version 1.4.0beta42, 43 [December 1, 2008]
-  Merge png_debug with version 1.2.34beta04.
-
-Version 1.4.0beta44 [December 6, 2008]
-  Removed redundant check for key==NULL before calling png_check_keyword()
-    to ensure that new_key gets initialized and removed extra warning
-    (Merge with version 1.2.34beta05 -- Arvan Pritchard).
-
-Version 1.4.0beta45 [December 9, 2008]
-  In png_write_png(), respect the placement of the filler bytes in an earlier
-    call to png_set_filler() (Jim Barry).
-
-Version 1.4.0beta46 [December 10, 2008]
-  Undid previous change and added PNG_TRANSFORM_STRIP_FILLER_BEFORE and
-    PNG_TRANSFORM_STRIP_FILLER_AFTER conditionals and deprecated
-    PNG_TRANSFORM_STRIP_FILLER (Jim Barry).
-
-Version 1.4.0beta47 [December 15, 2008]
-  Support for dithering was disabled by default, because it has never
-    been well tested and doesn't work very well.  The code has not
-    been removed, however, and can be enabled by building libpng with
-    PNG_READ_DITHER_SUPPORTED defined.
-
-Version 1.4.0beta48 [February 14, 2009]
-  Added new exported function png_calloc().
-  Combined several instances of png_malloc(); png_memset() into png_calloc().
-  Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
-    but was never defined.
-
-Version 1.4.0beta49 [February 28, 2009]
-  Added png_fileno() macro to pngconf.h, used in pngwio.c
-  Corrected order of #ifdef's in png_debug definition in png.h
-  Fixed bug introduced in libpng-1.4.0beta48 with the memset arguments
-    for pcal_params.
-  Fixed order of #ifdef directives in the png_debug defines in png.h
-    (bug introduced in libpng-1.2.34/1.4.0beta29).
-  Revised comments in png_set_read_fn() and png_set_write_fn().
-
-Version 1.4.0beta50 [March 18, 2009]
-  Use png_calloc() instead of png_malloc() to allocate big_row_buf when
-    reading an interlaced file, to avoid a possible UMR.
-  Undid revision of PNG_NO_STDIO version of png_write_flush().  Users
-    having trouble with fflush() can build with PNG_NO_WRITE_FLUSH defined
-    or supply their own flush_fn() replacement.
-  Revised libpng*.txt and png.h documentation about use of png_write_flush()
-    and png_set_write_fn().
-  Removed fflush() from pngtest.c.
-  Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
-
-Version 1.4.0beta51 [March 21, 2009]
-  Removed new png_fileno() macro from pngconf.h .
-
-Version 1.4.0beta52 [March 27, 2009]
-  Relocated png_do_chop() ahead of building gamma tables in pngrtran.c
-    This avoids building 16-bit gamma tables unnecessarily.
-  Removed fflush() from pngtest.c.
-  Added "#define PNG_NO_WRITE_FLUSH" to contrib/pngminim/encoder/pngusr.h
-  Added a section on differences between 1.0.x and 1.2.x to libpng.3/libpng.txt
-
-Version 1.4.0beta53 [April 1, 2009]
-  Removed some remaining MMX macros from pngpriv.h
-  Fixed potential memory leak of "new_name" in png_write_iCCP() (Ralph Giles)
-
-Version 1.4.0beta54 [April 13, 2009]
-  Added "ifndef PNG_SKIP_SETJMP_CHECK" block in pngconf.h to allow
-    application code writers to bypass the check for multiple inclusion
-    of setjmp.h when they know that it is safe to ignore the situation.
-  Eliminated internal use of setjmp() in pngread.c and pngwrite.c
-  Reordered ancillary chunks in pngtest.png to be the same as what
-    pngtest now produces, and made some cosmetic changes to pngtest output.
-  Eliminated deprecated png_read_init_3() and png_write_init_3() functions.
-
-Version 1.4.0beta55 [April 15, 2009]
-  Simplified error handling in pngread.c and pngwrite.c by putting
-    the new png_read_cleanup() and png_write_cleanup() functions inline.
-
-Version 1.4.0beta56 [April 25, 2009]
-  Renamed "user_chunk_data" to "my_user_chunk_data" in pngtest.c to suppress
-    "shadowed declaration" warning from gcc-4.3.3.
-  Renamed "gamma" to "png_gamma" in pngset.c to avoid "shadowed declaration"
-    warning about a global "gamma" variable in math.h on some platforms.
-
-Version 1.4.0beta57 [May 2, 2009]
-  Removed prototype for png_freeptr() that was added in libpng-1.4.0beta24
-    but was never defined (again).
-  Rebuilt configure scripts with autoconf-2.63 instead of 2.62
-  Removed pngprefs.h and MMX from makefiles
-
-Version 1.4.0beta58 [May 14, 2009]
-  Changed pngw32.def to pngwin.def in makefile.mingw (typo was introduced
-    in beta57).
-  Clarified usage of sig_bit versus sig_bit_p in example.c (Vincent Torri)
-
-Version 1.4.0beta59 [May 15, 2009]
-  Reformated sources in libpng style (3-space intentation, comment format)
-  Fixed typo in libpng docs (PNG_FILTER_AVE should be PNG_FILTER_AVG)
-  Added sections about the git repository and our coding style to the
-    documentation
-  Relocated misplaced #endif in pngwrite.c, sCAL chunk handler.
-
-Version 1.4.0beta60 [May 19, 2009]
-  Conditionally compile png_read_finish_row() which is not used by
-    progressive readers.
-  Added contrib/pngminim/preader to demonstrate building minimal progressive
-    decoder, based on contrib/gregbook with embedded libpng and zlib.
-
-Version 1.4.0beta61 [May 20, 2009]
-  In contrib/pngminim/*, renamed "makefile.std" to "makefile", since there
-    is only one makefile in those directories, and revised the README files
-    accordingly.
-  More reformatting of comments, mostly to capitalize sentences.
-
-Version 1.4.0beta62 [June 2, 2009]
-  Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h
-    and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h
-  Reformatted several remaining "else statement" into two lines.
-  Added a section to the libpng documentation about using png_get_io_ptr()
-    in configure scripts to detect the presence of libpng.
-
-Version 1.4.0beta63 [June 15, 2009]
-  Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR()
-    multiple times and to specify the sample order in the tRNS chunk,
-    because the ISO PNG specification has a typo in the tRNS table.
-  Changed several PNG_UNKNOWN_CHUNK_SUPPORTED to
-    PNG_HANDLE_AS_UNKNOWN_SUPPORTED, to make the png_set_keep mechanism
-    available for ignoring known chunks even when not saving unknown chunks.
-  Adopted preference for consistent use of "#ifdef" and "#ifndef" versus
-    "#if defined()" and "if !defined()" where possible.
-
-Version 1.4.0beta64 [June 24, 2009]
-  Eliminated PNG_LEGACY_SUPPORTED code.
-  Moved the various unknown chunk macro definitions outside of the
-    PNG_READ|WRITE_ANCILLARY_CHUNK_SUPPORTED blocks.
-
-Version 1.4.0beta65 [June 26, 2009]
-  Added a reference to the libpng license in each file.
-
-Version 1.4.0beta66 [June 27, 2009]
-  Refer to the libpng license instead of the libpng license in each file.
-
-Version 1.4.0beta67 [July 6, 2009]
-  Relocated INVERT_ALPHA within png_read_png() and png_write_png().
-  Added high-level API transform PNG_TRANSFORM_GRAY_TO_RGB.
-  Added an "xcode" project to the projects directory (Alam Arias).
-
-Version 1.4.0beta68 [July 19, 2009]
-  Avoid some tests in filter selection in pngwutil.c
-
-Version 1.4.0beta69 [July 25, 2009]
-  Simplified the new filter-selection test.  This runs faster in the
-    common "PNG_ALL_FILTERS" and PNG_FILTER_NONE cases.
-  Removed extraneous declaration from the new call to png_read_gray_to_rgb()
-    (bug introduced in libpng-1.4.0beta67).
-  Fixed up xcode project (Alam Arias)
-  Added a prototype for png_64bit_product() in png.c
-
-Version 1.4.0beta70 [July 27, 2009]
-  Avoid a possible NULL dereference in debug build, in png_set_text_2().
-    (bug introduced in libpng-0.95, discovered by Evan Rouault)
-
-Version 1.4.0beta71 [July 29, 2009]
-  Rebuilt configure scripts with autoconf-2.64.
-
-Version 1.4.0beta72 [August 1, 2009]
-  Replaced *.tar.lzma with *.tar.xz in distribution.  Get the xz codec
-    from <http://tukaani.org/xz>.
-
-Version 1.4.0beta73 [August 1, 2009]
-  Reject attempt to write iCCP chunk with negative embedded profile length
-    (JD Chen) (CVE-2009-5063).
-
-Version 1.4.0beta74 [August 8, 2009]
-  Changed png_ptr and info_ptr member "trans" to "trans_alpha".
-
-Version 1.4.0beta75 [August 21, 2009]
-  Removed an extra png_debug() recently added to png_write_find_filter().
-  Fixed incorrect #ifdef in pngset.c regarding unknown chunk support.
-
-Version 1.4.0beta76 [August 22, 2009]
-  Moved an incorrectly located test in png_read_row() in pngread.c
-
-Version 1.4.0beta77 [August 27, 2009]
-  Removed lpXYZ.tar.bz2 (with CRLF), KNOWNBUG, libpng-x.y.z-KNOWNBUG.txt,
-    and the "noconfig" files from the distribution.
-  Moved CMakeLists.txt from scripts into the main libpng directory.
-  Various bugfixes and improvements to CMakeLists.txt (Philip Lowman)
-
-Version 1.4.0beta78 [August 31, 2009]
-  Converted all PNG_NO_* tests to PNG_*_SUPPORTED everywhere except pngconf.h
-  Eliminated PNG_NO_FREE_ME and PNG_FREE_ME_SUPPORTED macros.
-  Use png_malloc plus a loop instead of png_calloc() to initialize
-    row_pointers in png_read_png().
-
-Version 1.4.0beta79 [September 1, 2009]
-  Eliminated PNG_GLOBAL_ARRAYS and PNG_LOCAL_ARRAYS; always use local arrays.
-  Eliminated PNG_CALLOC_SUPPORTED macro and always provide png_calloc().
-
-Version 1.4.0beta80 [September 17, 2009]
-  Removed scripts/libpng.icc
-  Changed typecast of filler from png_byte to png_uint_16 in png_set_filler().
-    (Dennis Gustafsson)
-  Fixed typo introduced in beta78 in pngtest.c ("#if def " should be "#ifdef ")
-
-Version 1.4.0beta81 [September 23, 2009]
-  Eliminated unused PNG_FLAG_FREE_* defines from pngpriv.h
-  Expanded TAB characters in pngrtran.c
-  Removed PNG_CONST from all "PNG_CONST PNG_CHNK" declarations to avoid
-    compiler complaints about doubly declaring things "const".
-  Changed all "#if [!]defined(X)" to "if[n]def X" where possible.
-  Eliminated unused png_ptr->row_buf_size
-
-Version 1.4.0beta82 [September 25, 2009]
-  Moved redundant IHDR checking into new png_check_IHDR() in png.c
-    and report all errors found in the IHDR data.
-  Eliminated useless call to png_check_cHRM() from pngset.c
-
-Version 1.4.0beta83 [September 25, 2009]
-  Revised png_check_IHDR() to eliminate bogus complaint about filter_type.
-
-Version 1.4.0beta84 [September 30, 2009]
-  Fixed some inconsistent indentation in pngconf.h
-  Revised png_check_IHDR() to add a test for width variable less than 32-bit.
-
-Version 1.4.0beta85 [October 1, 2009]
-  Revised png_check_IHDR() again, to check info_ptr members instead of
-    the contents of the returned parameters.
-
-Version 1.4.0beta86 [October 9, 2009]
-  Updated the "xcode" project (Alam Arias).
-  Eliminated a shadowed declaration of "pp" in png_handle_sPLT().
-
-Version 1.4.0rc01 [October 19, 2009]
-  Trivial cosmetic changes.
-
-Version 1.4.0beta87 [October 30, 2009]
-  Moved version 1.4.0 back into beta.
-
-Version 1.4.0beta88 [October 30, 2009]
-  Revised libpng*.txt section about differences between 1.2.x and 1.4.0
-    because most of the new features have now been ported back to 1.2.41
-
-Version 1.4.0beta89 [November 1, 2009]
-  More bugfixes and improvements to CMakeLists.txt (Philip Lowman)
-  Removed a harmless extra png_set_invert_alpha() from pngwrite.c
-  Apply png_user_chunk_cache_max within png_decompress_chunk().
-  Merged libpng-1.2.41.txt with libpng-1.4.0.txt where appropriate.
-
-Version 1.4.0beta90 [November 2, 2009]
-  Removed all remaining WIN32_WCE #ifdefs except those involving the
-    time.h "tm" structure
-
-Version 1.4.0beta91 [November 3, 2009]
-  Updated scripts/pngw32.def and projects/wince/png32ce.def
-  Copied projects/wince/png32ce.def to the scripts directory.
-  Added scripts/makefile.wce
-  Patched ltmain.sh for wince support.
-  Added PNG_CONVERT_tIME_SUPPORTED macro.
-
-Version 1.4.0beta92 [November 4, 2009]
-  Make inclusion of time.h in pngconf.h depend on PNG_CONVERT_tIME_SUPPORTED
-  Make #define PNG_CONVERT_tIME_SUPPORTED depend on PNG_WRITE_tIME_SUPPORTED
-  Revised libpng*.txt to describe differences from 1.2.40 to 1.4.0 (instead
-    of differences from 1.2.41 to 1.4.0)
-
-Version 1.4.0beta93 [November 7, 2009]
-  Added PNG_DEPSTRUCT, PNG_DEPRECATED, PNG_USE_RESULT, PNG_NORETURN, and
-    PNG_ALLOCATED macros to detect deprecated direct access to the
-    png_struct or info_struct members and other deprecated usage in
-    applications (John Bowler).
-  Updated scripts/makefile* to add "-DPNG_CONFIGURE_LIBPNG" to CFLAGS,
-    to prevent warnings about direct access to png structs by libpng
-    functions while building libpng.  They need to be tested, especially
-    those using compilers other than gcc.
-  Updated projects/visualc6 and visualc71 with "/d PNG_CONFIGURE_LIBPNG".
-    They should work but still need to be updated to remove
-    references to pnggccrd.c or pngvcrd.c and ASM building.
-  Added README.txt to the beos, cbuilder5, netware, and xcode projects warning
-    that they need to be updated, to remove references to pnggccrd.c and
-    pngvcrd.c and to depend on pngpriv.h
-  Removed three direct references to read_info_ptr members in pngtest.c
-    that were detected by the new PNG_DEPSTRUCT macro.
-  Moved the png_debug macro definitions and the png_read_destroy(),
-    png_write_destroy() and png_far_to_near() prototypes from png.h
-    to pngpriv.h (John Bowler)
-  Moved the synopsis lines for png_read_destroy(), png_write_destroy()
-    png_debug(), png_debug1(), and png_debug2() from libpng.3 to libpngpf.3.
-
-Version 1.4.0beta94 [November 9, 2009]
-  Removed the obsolete, unused pnggccrd.c and pngvcrd.c files.
-  Updated CMakeLists.txt to add "-DPNG_CONFIGURE_LIBPNG" to the definitions.
-  Removed dependency of pngtest.o on pngpriv.h in the makefiles.
-  Only #define PNG_DEPSTRUCT, etc. in pngconf.h if not already defined.
-
-Version 1.4.0beta95 [November 10, 2009]
-  Changed png_check_sig() to !png_sig_cmp() in contrib programs.
-  Added -DPNG_CONFIGURE_LIBPNG to contrib/pngminm/*/makefile
-  Changed png_check_sig() to !png_sig_cmp() in contrib programs.
-  Corrected the png_get_IHDR() call in contrib/gregbook/readpng2.c
-  Changed pngminim/*/gather.sh to stop trying to remove pnggccrd.c and pngvcrd.c
-  Added dependency on pngpriv.h in contrib/pngminim/*/makefile
-
-Version 1.4.0beta96 [November 12, 2009]
-  Renamed scripts/makefile.wce to scripts/makefile.cegcc
-  Revised Makefile.am to use libpng.sys while building libpng.so
-    so that only PNG_EXPORT functions are exported.
-  Removed the deprecated png_check_sig() function/macro.
-  Removed recently removed function names from scripts/*.def
-  Revised pngtest.png to put chunks in the same order written by pngtest
-    (evidently the same change made in libpng-1.0beta54 was lost).
-  Added PNG_PRIVATE macro definition in pngconf.h for possible future use.
-
-Version 1.4.0beta97 [November 13, 2009]
-  Restored pngtest.png to the libpng-1.4.0beta7 version.
-  Removed projects/beos and netware.txt; no one seems to be supporting them.
-  Revised Makefile.in
-
-Version 1.4.0beta98 [November 13, 2009]
-  Added the "xcode" project to zip distributions,
-  Fixed a typo in scripts/pngwin.def introduced in beta97.
-
-Version 1.4.0beta99 [November 14, 2009]
-  Moved libpng-config.in and libpng.pc-configure.in out of the scripts
-    directory, to libpng-config.in and libpng-pc.in, respectively, and
-    modified Makefile.am and configure.ac accordingly.  Now "configure"
-    needs nothing from the "scripts" directory.
-  Avoid redefining PNG_CONST in pngconf.h
-
-Version 1.4.0beta100 [November 14, 2009]
-  Removed ASM builds from projects/visualc6 and projects/visualc71
-  Removed scripts/makefile.nommx and makefile.vcawin32
-  Revised CMakeLists.txt to account for new location of libpng-config.in
-    and libpng-pc.in
-  Updated INSTALL to reflect removal and relocation of files.
-
-Version 1.4.0beta101 [November 14, 2009]
-  Restored the binary files (*.jpg, *.png, some project files) that were
-    accidentally deleted from the zip and 7z distributions when the xcode
-    project was added.
-
-Version 1.4.0beta102 [November 18, 2009]
-  Added libpng-config.in and libpng-pc.in to the zip and 7z distributions.
-  Fixed a typo in projects/visualc6/pngtest.dsp, introduced in beta100.
-  Moved descriptions of makefiles and other scripts out of INSTALL into
-    scripts/README.txt
-  Updated the copyright year in scripts/pngwin.rc from 2006 to 2009.
-
-Version 1.4.0beta103 [November 21, 2009]
-  Removed obsolete comments about ASM from projects/visualc71/README_zlib.txt
-  Align row_buf on 16-byte boundary in memory.
-  Restored the PNG_WRITE_FLUSH_AFTER_IEND_SUPPORTED guard around the call
-    to png_flush() after png_write_IEND().  See 1.4.0beta32, 1.4.0beta50
-    changes above and 1.2.30, 1.2.30rc01 and rc03 in 1.2.41 CHANGES.  Someone
-    needs this feature.
-  Make the 'png_jmpbuf' macro expand to a call that records the correct
-    longjmp function as well as returning a pointer to the setjmp
-    jmp_buf buffer, and marked direct access to jmpbuf 'deprecated'.
-    (John Bowler)
-
-Version 1.4.0beta104 [November 22, 2009]
-  Removed png_longjmp_ptr from scripts/*.def and libpng.3
-  Rebuilt configure scripts with autoconf-2.65
-
-Version 1.4.0beta105 [November 25, 2009]
-  Use fast integer PNG_DIVIDE_BY_255() or PNG_DIVIDE_BY_65535()
-    to accomplish alpha premultiplication when
-    PNG_READ_COMPOSITE_NODIV_SUPPORTED is defined.
-  Changed "/255" to "/255.0" in background calculations to make it clear
-    that the 255 is used as a double.
-
-Version 1.4.0beta106 [November 27, 2009]
-  Removed premultiplied alpha feature.
-
-Version 1.4.0beta107 [December 4, 2009]
-  Updated README
-  Added "#define PNG_NO_PEDANTIC_WARNINGS" in the libpng source files.
-  Removed "-DPNG_CONFIGURE_LIBPNG" from the makefiles and projects.
-  Revised scripts/makefile.netbsd, makefile.openbsd, and makefile.sco
-    to put png.h and pngconf.h in $prefix/include, like the other scripts,
-    instead of in $prefix/include/libpng.  Also revised makefile.sco
-    to put them in $prefix/include/libpng15 instead of in
-    $prefix/include/libpng/libpng15.
-
-Version 1.4.0beta108 [December 11, 2009]
-  Removed leftover "-DPNG_CONFIGURE_LIBPNG" from contrib/pngminim/*/makefile
-  Relocated png_do_chop() to its original position in pngrtran.c; the
-    change in version 1.2.41beta08 caused transparency to be handled wrong
-    in some 16-bit datastreams (Yusaku Sugai).
-
-Version 1.4.0beta109 [December 13, 2009]
-  Added "bit_depth" parameter to the private png_build_gamma_table() function.
-  Pass bit_depth=8 to png_build_gamma_table() when bit_depth is 16 but the
-    PNG_16_TO_8 transform has been set, to avoid unnecessary build of 16-bit
-    tables.
-
-Version 1.4.0rc02 [December 20, 2009]
-  Declared png_cleanup_needed "volatile" in pngread.c and pngwrite.c
-
-Version 1.4.0rc03 [December 22, 2009]
-  Renamed libpng-pc.in back to libpng.pc.in and revised CMakeLists.txt
-    (revising the change in 1.4.0beta99)
-
-Version 1.4.0rc04 [December 25, 2009]
-  Swapped PNG_UNKNOWN_CHUNKS_SUPPORTED and PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-    in pngset.c to be consistent with other changes in version 1.2.38.
-
-Version 1.4.0rc05 [December 25, 2009]
-  Changed "libpng-pc.in" to "libpng.pc.in" in configure.ac, configure, and
-    Makefile.in to be consistent with changes in libpng-1.4.0rc03
-
-Version 1.4.0rc06 [December 29, 2009]
-  Reverted the gamma_table changes from libpng-1.4.0beta109.
-  Fixed some indentation errors.
-
-Version 1.4.0rc07 [January 1, 2010]
-  Revised libpng*.txt and libpng.3 about 1.2.x->1.4.x differences.
-  Use png_calloc() instead of png_malloc(); png_memset() in pngrutil.c
-  Update copyright year to 2010.
-
-Version 1.4.0rc08 [January 2, 2010]
-  Avoid deprecated references to png_ptr-io_ptr and png_ptr->error_ptr
-    in pngtest.c
-
-Version 1.4.0 [January 3, 2010]
-  No changes.
-
-Version 1.4.1beta01 [January 8, 2010]
-  Updated CMakeLists.txt for consistent indentation and to avoid an
-    unclosed if-statement warning (Philip Lowman).
-  Revised Makefile.am and Makefile.in to remove references to Y2KINFO,
-    KNOWNBUG, and libpng.la (Robert Schwebel).
-  Revised the makefiles to install the same files and symbolic
-    links as configure, except for libpng.la and libpng14.la.
-  Make png_set|get_compression_buffer_size() available even when
-    PNG_WRITE_SUPPORTED is not enabled.
-  Revised Makefile.am and Makefile.in to simplify their maintenance.
-  Revised scripts/makefile.linux to install a link to libpng14.so.14.1
-
-Version 1.4.1beta02 [January 9, 2010]
-  Revised the rest of the makefiles to install a link to libpng14.so.14.1
-
-Version 1.4.1beta03 [January 10, 2010]
-  Removed png_set_premultiply_alpha() from scripts/*.def
-
-Version 1.4.1rc01 [January 16, 2010]
-  No changes.
-
-Version 1.4.1beta04 [January 23, 2010]
-  Revised png_decompress_chunk() to improve speed and memory usage when
-    decoding large chunks.
-  Added png_set|get_chunk_malloc_max() functions.
-
-Version 1.4.1beta05 [January 26, 2010]
-  Relocated "int k" declaration in pngtest.c to minimize its scope.
-
-Version 1.4.1beta06 [January 28, 2010]
-  Revised png_decompress_chunk() to use a two-pass method suggested by
-    John Bowler.
-
-Version 1.4.1beta07 [February 6, 2010]
-  Folded some long lines in the source files.
-  Added defineable PNG_USER_CHUNK_CACHE_MAX, PNG_USER_CHUNK_MALLOC_MAX,
-    and a PNG_USER_LIMITS_SUPPORTED flag.
-  Eliminated use of png_ptr->irowbytes and reused the slot in png_ptr as
-    png_ptr->png_user_chunk_malloc_max.
-  Revised png_push_save_buffer() to do fewer but larger png_malloc() calls.
-
-Version 1.4.1beta08 [February 6, 2010]
-  Minor cleanup and updating of dates and copyright year.
-
-Version 1.5.0beta01 [February 7, 2010]
-  Moved declaration of png_struct into private pngstruct.h and png_info
-    into pnginfo.h
-
-Version 1.4.1beta09 and 1.5.0beta02 [February 7, 2010]
-  Reverted to original png_push_save_buffer() code.
-
-Version 1.4.1beta10 and 1.5.0beta03 [February 8, 2010]
-  Return allocated "old_buffer" in png_push_save_buffer() before
-    calling png_error(), to avoid a potential memory leak.
-  Updated configure script to use SO number 15.
-
-Version 1.5.0beta04 [February 9, 2010]
-  Removed malformed "incomplete struct declaration" of png_info from png.h
-
-Version 1.5.0beta05 [February 12, 2010]
-  Removed PNG_DEPSTRUCT markup in pngstruct.h and pnginfo.h, and undid the
-    linewrapping that it entailed.
-  Revised comments in pngstruct.h and pnginfo.h and added pointers to
-    the libpng license.
-  Changed PNG_INTERNAL to PNG_EXPOSE_INTERNAL_STRUCTURES
-  Removed the cbuilder5 project, which has not been updated to 1.4.0.
-
-Version 1.4.1beta12 and 1.5.0beta06 [February 14, 2010]
-  Fixed type declaration of png_get_chunk_malloc_max() in pngget.c (Daisuke
-    Nishikawa)
-
-Version 1.5.0beta07 [omitted]
-
-Version 1.5.0beta08 [February 19, 2010]
-  Changed #ifdef PNG_NO_STDIO_SUPPORTED to #ifdef PNG_NO_CONSOLE_IO_SUPPORTED
-    wherever png_snprintf() is used to construct error and warning messages.
-  Noted in scripts/makefile.mingw that it expects to be run under MSYS.
-  Removed obsolete unused MMX-querying support from contrib/gregbook
-  Added exported png_longjmp() function.
-  Removed the AIX redefinition of jmpbuf in png.h
-  Added -D_ALLSOURCE in configure.ac, makefile.aix, and CMakeLists.txt
-    when building on AIX.
-
-Version 1.5.0beta09 [February 19, 2010]
-  Removed -D_ALLSOURCE from configure.ac, makefile.aix, and CMakeLists.txt.
-  Changed the name of png_ptr->jmpbuf to png_ptr->png_jmpbuf in pngstruct.h
-
-Version 1.5.0beta10 [February 25, 2010]
-  Removed unused gzio.c from contrib/pngminim gather and makefile scripts
-  Removed replacement error handlers from contrib/gregbook.  Because of
-    the new png_longjmp() function they are no longer needed.
-
-Version 1.5.0beta11 [March 6, 2010]
-  Removed checking for already-included setjmp.h from pngconf.h
-  Fixed inconsistent indentations and made numerous cosmetic changes.
-  Revised the "SEE ALSO" style of libpng.3, libpngpf.3, and png.5
-
-Version 1.5.0beta12 [March 9, 2010]
-  Moved "#include png.h" inside pngpriv.h and removed "#include png.h" from
-    the source files, along with "#define PNG_EXPOSE_INTERNAL_STRUCTURES"
-    and "#define PNG_NO_PEDANTIC_WARNINGS" (John Bowler).
-  Created new pngdebug.h and moved debug definitions there.
-
-Version 1.5.0beta13 [March 10, 2010]
-  Protect pngstruct.h, pnginfo.h, and pngdebug.h from being included twice.
-  Revise the "#ifdef" blocks in png_inflate() so it will compile when neither
-    PNG_USER_CHUNK_MALLOC_MAX nor PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED
-    is defined.
-  Removed unused png_measure_compressed_chunk() from pngpriv.h and libpngpf.3
-  Moved the 'config.h' support from pngconf.h to pngpriv.h
-  Removed PNGAPI from the png_longjmp_ptr typedef.
-  Eliminated dependence of pngtest.c on the private pngdebug.h file.
-  Make all png_debug macros into *unterminated* statements or
-    expressions (i.e. a trailing ';' must always be added) and correct
-    the format statements in various png_debug messages.
-
-Version 1.5.0beta14 [March 14, 2010]
-  Removed direct access to png_ptr->io_ptr from the Windows code in pngtest.c
-  Revised Makefile.am to account for recent additions and replacements.
-  Corrected CE and OS/2 DEF files (scripts/png*def) for symbols removed and
-    added ordinal numbers to the Windows DEF file and corrected the duplicated
-    ordinal numbers on CE symbols that are commented out.
-  Added back in export symbols that can be present in the Windows build but
-    are disabled by default.
-  PNG_EXPORT changed to include an 'ordinal' field for DEF file generation.
-    PNG_CALLBACK added to make callback definitions uniform.  PNGAPI split
-    into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks),
-    and appropriate changes made to all files.  Cygwin builds re-hinged to
-    allow procedure call standard changes and to remove the need for the DEF
-    file (fixes build on Cygwin).
-  Enabled 'attribute' warnings that are relevant to library APIs and callbacks.
-  Changed rules for generation of the various symbol files and added a new
-    rule for a DEF file (which is also added to the distribution).
-  Updated the symbol file generation to stop it adding spurious spaces
-    to EOL (coming from preprocessor macro expansion).  Added a facility
-    to join tokens in the output and rewrite *.dfn to use this.
-  Eliminated scripts/*.def in favor of libpng.def; updated projects/visualc71
-    and removed scripts/makefile.cygwin.
-  Made PNG_BUILD_DLL safe: it can be set whenever a DLL is being built.
-  Removed the include of sys/types.h - apparently unnecessary now on the
-    platforms on which it happened (all but Mac OS and RISC OS).
-  Moved the Mac OS test into pngpriv.h (the only place it is used.)
-
-Version 1.5.0beta15 [March 17, 2010]
-  Added symbols.chk target to Makefile.am to validate the symbols in png.h
-    against the new DEF file scripts/symbols.def.
-  Changed the default DEF file back to pngwin.def.
-  Removed makefile.mingw.
-  Eliminated PNG_NO_EXTERN and PNG_ALL_EXTERN
-
-Version 1.5.0beta16 [April 1, 2010]
-  Make png_text_struct independent of PNG_iTXt_SUPPORTED, so that
-    fields are initialized in all configurations.  The READ/WRITE
-    macros (PNG_(READ|WRITE)_iTXt_SUPPORTED) still function as
-    before to disable code to actually read or write iTXt chunks
-    and iTXt_SUPPORTED can be used to detect presence of either
-    read or write support (but it is probably better to check for
-    the one actually required - read or write.)
-  Combined multiple png_warning() calls for a single error.
-  Restored the macro definition of png_check_sig().
-
-Version 1.5.0beta17 [April 17, 2010]
-  Added some "(long)" typecasts to printf calls in png_handle_cHRM().
-  Documented the fact that png_set_dither() was disabled since libpng-1.4.0.
-  Reenabled png_set_dither() but renamed it to png_set_quantize() to reflect
-    more accurately what it actually does.  At the same time, renamed
-    the PNG_DITHER_[RED,GREEN_BLUE]_BITS macros to
-    PNG_QUANTIZE_[RED,GREEN,BLUE]_BITS.
-  Added some "(long)" typecasts to printf calls in png_handle_cHRM().
-  Freeze build-time only configuration in the build.
-    In all prior versions of libpng most configuration options
-    controlled by compiler #defines had to be repeated by the
-    application code that used libpng.  This patch changes this
-    so that compilation options that can only be changed at build
-    time are frozen in the build.  Options that are compiler
-    dependent (and those that are system dependent) are evaluated
-    each time - pngconf.h holds these.  Options that can be changed
-    per-file in the application are in png.h.  Frozen options are
-    in the new installed header file pnglibconf.h (John Bowler)
-  Removed the xcode project because it has not been updated to work
-    with libpng-1.5.0.
-  Removed the ability to include optional pngusr.h
-
-Version 1.5.0beta18 [April 17, 2010]
-  Restored the ability to include optional pngusr.h
-  Moved replacements for png_error() and png_warning() from the
-    contrib/pngminim project to pngerror.c, for use when warnings or
-    errors are disabled via PNG_NO_WARN or PNG_NO_ERROR_TEXT, to avoid
-    storing unneeded error/warning text.
-  Updated contrib/pngminim project to work with the new pnglibconf.h
-  Added some PNG_NO_* defines to contrib/pngminim/*/pngusr.h to save space.
-
-Version 1.5.0beta19 [April 24, 2010]
-  Added PNG_{READ,WRITE}_INT_FUNCTIONS_SUPPORTED.  This allows the functions
-    to read and write ints to be disabled independently of PNG_USE_READ_MACROS,
-    which allows libpng to be built with the functions even though the default
-    is to use the macros - this allows applications to choose at app build
-    time whether or not to use macros (previously impossible because the
-    functions weren't in the default build.)
-  Changed Windows calling convention back to __cdecl for API functions.
-    For Windows/x86 platforms only:
-      __stdcall is no longer needed for Visual Basic, so libpng-1.5.0 uses
-      __cdecl throughout (both API functions and callbacks) on Windows/x86
-      platforms.
-  Replaced visualc6 and visualc71 projects with new vstudio project
-  Relaxed the overly-restrictive permissions of some files.
-
-Version 1.5.0beta20 [April 24, 2010]
-  Relaxed more overly-restrictive permissions of some files.
-
-Version 1.5.0beta21 [April 27, 2010]
-  Removed some unwanted binary bytes and changed CRLF to NEWLINE in the new
-    vstudio project files, and some trivial editing of some files in the
-    scripts directory.
-  Set PNG_NO_READ_BGR, PNG_NO_IO_STATE, and PNG_NO_TIME_RFC1123 in
-    contrib/pngminim/decoder/pngusr.h to make a smaller decoder application.
-
-Version 1.5.0beta22 [April 28, 2010]
-  Fixed dependencies of GET_INT_32 - it does not require READ_INT_FUNCTIONS
-    because it has a macro equivalent.
-  Improved the options.awk script; added an "everything off" option.
-  Revised contrib/pngminim to use the "everything off" option in pngusr.dfa.
-
-Version 1.5.0beta23 [April 29, 2010]
-  Corrected PNG_REMOVED macro to take five arguments.
-    The macro was documented with two arguments (name,ordinal), however
-    the symbol checking .dfn files assumed five arguments.  The five
-    argument form seems more useful so it is changed to that.
-  Corrected PNG_UNKNOWN_CHUNKS_SUPPORTED to PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-    in gregbook/readpng2.c
-  Corrected protection of png_get_user_transform_ptr. The API declaration in
-    png.h is removed if both READ and WRITE USER_TRANSFORM are turned off
-    but was left defined in pngtrans.c
-  Added logunsupported=1 to cause pnglibconf.h to document disabled options.
-    This makes the installed pnglibconf.h more readable but causes no
-    other change.  The intention is that users of libpng will find it
-    easier to understand if an API they need is missing.
-  Include png_reset_zstream() in png.c only when PNG_READ_SUPPORTED is defined.
-  Removed dummy_inflate.c from contrib/pngminim/encoder
-  Removed contrib/pngminim/*/gather.sh; gathering is now done in the makefile.
-
-Version 1.5.0beta24 [May 7, 2010]
-  Use bitwise "&" instead of arithmetic mod in pngrutil.c calculation of the
-    offset of the png_ptr->rowbuf pointer into png_ptr->big_row_buf.
-  Added more blank lines for readability.
-
-Version 1.5.0beta25 [June 18, 2010]
-  In pngpread.c: png_push_have_row() add check for new_row > height
-  Removed the now-redundant check for out-of-bounds new_row from example.c
-
-Version 1.5.0beta26 [June 18, 2010]
-  In pngpread.c: png_push_process_row() add check for too many rows.
-
-Version 1.5.0beta27 [June 18, 2010]
-  Removed the check added in beta25 as it is now redundant.
-
-Version 1.5.0beta28 [June 20, 2010]
-  Rewrote png_process_IDAT_data to consistently treat extra data as warnings
-    and handle end conditions more cleanly.
-  Removed the new (beta26) check in png_push_process_row().
-
-Version 1.5.0beta29 [June 21, 2010]
-  Revised scripts/options.awk to work on Sunos (but still doesn't work)
-  Added comment to options.awk and contrib/pngminim/*/makefile to try nawk.
-
-Version 1.5.0beta30 [June 22, 2010]
-  Stop memory leak when reading a malformed sCAL chunk.
-
-Version 1.5.0beta31 [June 26, 2010]
-  Revised pngpread.c patch of beta28 to avoid an endless loop.
-  Removed some trailing blanks.
-
-Version 1.5.0beta32 [June 26, 2010]
-  Removed leftover scripts/options.patch and scripts/options.rej
-
-Version 1.5.0beta33 [July 6, 3010]
-  Made FIXED and FLOATING options consistent in the APIs they enable and
-    disable.  Corrected scripts/options.awk to handle both command line
-    options and options specified in the .dfa files.
-  Changed char *msg to PNG_CONST char *msg in pngrutil.c
-  Make png_set_sRGB_gAMA_and_cHRM set values using either the fixed or
-    floating point APIs, but not both.
-  Reversed patch to remove error handler when the jmp_buf is stored in the
-    main program structure, not the png_struct.
-    The error handler is needed because the default handler in libpng will
-    always use the jmp_buf in the library control structure; this is never
-    set.  The gregbook code is a useful example because, even though it
-    uses setjmp/longjmp, it shows how error handling can be implemented
-    using control mechanisms not directly supported by libpng.  The
-    technique will work correctly with mechanisms such as Microsoft
-    Structure Exceptions or C++ exceptions (compiler willing - note that gcc
-    does not by default support interworking of C and C++ error handling.)
-  Reverted changes to call png_longjmp in contrib/gregbook where it is not
-    appropriate.  If mainprog->jmpbuf is used by setjmp, then png_longjmp
-    cannot be used.
-  Changed "extern PNG_EXPORT" to "PNG_EXPORT" in png.h (Jan Nijtmans)
-  Changed "extern" to "PNG_EXTERN" in pngpriv.h (except for the 'extern "C" {')
-
-Version 1.5.0beta34 [July 12, 2010]
-  Put #ifndef PNG_EXTERN, #endif around the define PNG_EXTERN in pngpriv.h
-
-Version 1.5.0beta35 [July 24, 2010]
-  Removed some newly-added TAB characters.
-  Added -DNO_PNG_SNPRINTF to CFLAGS in scripts/makefile.dj2
-  Moved the definition of png_snprintf() outside of the enclosing
-    #ifdef blocks in pngconf.h
-
-Version 1.5.0beta36 [July 29, 2010]
-  Patches by John Bowler:
-  Fixed point APIs are now supported throughout (no missing APIs).
-  Internal fixed point arithmetic support exists for all internal floating
-    point operations.
-  sCAL validates the floating point strings it is passed.
-  Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2
-  Two new APIs exist to get the number of passes without turning on the
-    PNG_INTERLACE transform and to get the number of rows in the current
-    pass.
-  A new test program, pngvalid.c, validates the gamma code.
-  Errors in the 16-bit gamma correction (overflows) have been corrected.
-  cHRM chunk testing is done consistently (previously the floating point
-    API bypassed it, because the test really didn't work on FP, now the test
-    is performed on the actual values to be stored in the PNG file so it
-    works in the FP case too.)
-  Most floating point APIs now simply call the fixed point APIs after
-    converting the values to the fixed point form used in the PNG file.
-  The standard headers no longer include zlib.h, which is currently only
-    required for pngstruct.h and can therefore be internal.
-  Revised png_get_int_32 to undo the PNG two's complement representation of
-    negative numbers.
-
-Version 1.5.0beta37 [July 30, 2010]
-  Added a typecast in png_get_int_32() in png.h and pngrutil.h to avoid
-    a compiler warning.
-  Replaced oFFs 0,0 with oFFs -10,20 in pngtest.png
-
-Version 1.5.0beta38 [July 31, 2010]
-  Implemented remaining "_fixed" functions.
-  Corrected a number of recently introduced warnings mostly resulting from
-    safe but uncast assignments to shorter integers.  Also added a zlib
-    VStudio release library project because the latest zlib Official Windows
-    build does not include such a thing.
-  Revised png_get_int_16() to be similar to png_get_int_32().
-  Restored projects/visualc71.
-
-Version 1.5.0beta39 [August 2, 2010]
-  VisualC/GCC warning fixes, VisualC build fixes
-  The changes include support for function attributes in VC in addition to
-    those already present in GCC - necessary because without these some
-    warnings are unavoidable.  Fixes include signed/unsigned fixes in
-    pngvalid and checks with gcc -Wall -Wextra -Wunused.
-  VC requires function attributes on function definitions as well as
-    declarations, PNG_FUNCTION has been added to enable this and the
-    relevant function definitions changed.
-
-Version 1.5.0beta40 [August 6, 2010]
-  Correct use of _WINDOWS_ in pngconf.h
-  Removed png_mem_ #defines; they are no longer used.
-  Added the sRGB chunk to pngtest.png
-
-Version 1.5.0beta41 [August 11, 2010]
-  Added the cHRM chunk to pngtest.png
-  Don't try to use version-script with cygwin/mingw.
-  Revised contrib/gregbook to work under cygwin/mingw.
-
-Version 1.5.0beta42 [August 18, 2010]
-  Add .dll.a to the list of extensions to be symlinked by Makefile.am (Yaakov)
-  Made all API functions that have const arguments and constant string
-    literal pointers declare them (John Bowler).
-
-Version 1.5.0beta43 [August 20, 2010]
-  Removed spurious tabs, shorten long lines (no source change)
-    Also added scripts/chkfmt to validate the format of all the files that can
-    reasonably be validated (it is suggested to run "make distclean" before
-    checking, because some machine generated files have long lines.)
-  Reformatted the CHANGES file to be more consistent throughout.
-  Made changes to address various issues identified by GCC, mostly
-    signed/unsigned and shortening problems on assignment but also a few
-    difficult to optimize (for GCC) loops.
-  Fixed non-GCC fixed point builds.  In png.c a declaration was misplaced
-    in an earlier update.  Fixed to declare the auto variables at the head.
-  Use cexcept.h in pngvalid.c.
-
-Version 1.5.0beta44 [August 24, 2010]
-  Updated CMakeLists.txt to use CMAKE_INSTALL_LIBDIR variable; useful for
-    installing libpng in /usr/lib64 (Funda Wang).
-  Revised CMakeLists.txt to put the man pages in share/man/man* not man/man*
-  Revised CMakeLists.txt to make symlinks instead of copies when installing.
-  Changed PNG_LIB_NAME from pngNN to libpngNN in CMakeLists.txt (Philip Lowman)
-  Implemented memory checks within pngvalid
-  Reformatted/rearranged pngvalid.c to assist use of progressive reader.
-  Check interlaced images in pngvalid
-  Clarified pngusr.h comments in pnglibconf.dfa
-  Simplified the pngvalid error-handling code now that cexcept.h is in place.
-  Implemented progressive reader in pngvalid.c for standard tests
-  Implemented progressive read in pngvalid.c gamma tests
-  Turn on progressive reader in pngvalid.c by default and tidy code.
-
-Version 1.5.0beta45 [August 26, 2010]
-  Added an explicit make step to projects/vstudio for pnglibconf.h
-    Also corrected zlib.vcxproj into which Visual Studio had introduced
-    what it calls an "authoring error".  The change to make pnglibconf.h
-    simply copies the file; in the future it may actually generate the
-    file from scripts/pnglibconf.dfa as the other build systems do.
-  Changed pngvalid to work when floating point APIs are disabled
-  Renamed the prebuilt scripts/pnglibconf.h to scripts/pnglibconf.h.prebuilt
-  Supply default values for PNG_USER_PRIVATEBUILD and PNG_USER_DLLFNAME_POSTFIX
-    in pngpriv.h in case the user neglected to define them in their pngusr.h
-
-Version 1.5.0beta46 [August 28, 2010]
-  Added new private header files to libpng_sources in CMakeLists.txt
-  Added PNG_READ_16BIT, PNG_WRITE_16BIT, and PNG_16BIT options.
-  Added reference to scripts/pnglibconf.h.prebuilt in the visualc71 project.
-
-Version 1.5.0beta47 [September 11, 2010]
-  Fixed a number of problems with 64-bit compilation reported by Visual
-    Studio 2010 (John Bowler).
-
-Version 1.5.0beta48 [October 4, 2010]
-  Updated CMakeLists.txt (Philip Lowman).
-  Revised autogen.sh to recognize and use $AUTOCONF, $AUTOMAKE, $AUTOHEADER,
-    $AUTOPOINT, $ACLOCAL and $LIBTOOLIZE
-  Fixed problem with symbols creation in Makefile.am which was assuming that
-    all versions of ccp write to standard output by default (Martin Banky). The
-    bug was introduced in libpng-1.2.9beta5.
-  Removed unused mkinstalldirs.
-
-Version 1.5.0beta49 [October 8, 2010]
-  Undid Makefile.am revision of 1.5.0beta48.
-
-Version 1.5.0beta50 [October 14, 2010]
-  Revised Makefile.in to account for mkinstalldirs being removed.
-  Added some "(unsigned long)" typecasts in printf statements in pngvalid.c.
-  Suppressed a compiler warning in png_handle_sPLT().
-  Check for out-of-range text compression mode in png_set_text().
-
-Version 1.5.0beta51 [October 15, 2010]
-  Changed embedded dates to "(PENDING RELEASE) in beta releases (and future
-    rc releases) to minimize the difference between releases.
-
-Version 1.5.0beta52 [October 16, 2010]
-  Restored some of the embedded dates (in png.h, png.c, documentation, etc.)
-
-Version 1.5.0beta53 [October 18, 2010]
-  Updated INSTALL to mention using "make maintainer-clean" and to remove
-    obsolete statement about a custom ltmain.sh
-  Disabled "color-tests" by default in Makefile.am so it will work with
-    automake versions earlier than 1.11.1
-  Use document name "libpng-manual.txt" instead of "libpng-<version>.txt"
-    to simplify version differences.
-  Removed obsolete remarks about setjmp handling from INSTALL.
-  Revised and renamed the typedef in png.h and png.c that was designed
-    to catch library and header mismatch.
-
-Version 1.5.0beta54 [November 10, 2010]
-  Require 48 bytes, not 64 bytes, for big_row_buf in overflow checks.
-  Used a consistent structure for the pngget.c functions.
-
-Version 1.5.0beta55 [November 21, 2010]
-  Revised png_get_uint_32, png_get_int_32, png_get_uint_16 (Cosmin)
-  Moved reading of file signature into png_read_sig (Cosmin)
-  Fixed atomicity of chunk header serialization (Cosmin)
-  Added test for io_state in pngtest.c (Cosmin)
-  Added "#!/bin/sh" at the top of contrib/pngminim/*/gather.sh scripts.
-  Changes to remove gcc warnings (John Bowler)
-    Certain optional gcc warning flags resulted in warnings in libpng code.
-    With these changes only -Wconversion and -Wcast-qual cannot be turned on.
-    Changes are trivial rearrangements of code.  -Wconversion is not possible
-    for pngrutil.c (because of the widespread use of += et al on variables
-    smaller than (int) or (unsigned int)) and -Wcast-qual is not possible
-    with pngwio.c and pngwutil.c because the 'write' callback and zlib
-    compression both fail to declare their input buffers with 'const'.
-
-Version 1.5.0beta56 [December 7, 2010]
-  Added the private PNG_UNUSED() macro definition in pngpriv.h.
-  Added some commentary about PNG_EXPORT in png.h and pngconf.h
-  Revised PNG_EXPORT() macro and added PNG_EXPORTA() macro, with the
-    objective of simplifying and improving the cosmetic appearance of png.h.
-  Fixed some incorrect "=" macro names in pnglibconf.dfa
-  Included documentation of changes in 1.5.0 from 1.4.x in libpng-manual.txt
-
-Version 1.5.0beta57 [December 9, 2010]
-  Documented the pngvalid gamma error summary with additional comments and
-    print statements.
-  Improved missing symbol handling in checksym.awk; symbols missing in both
-    the old and new files can now be optionally ignored, treated as errors
-    or warnings.
-  Removed references to pngvcrd.c and pnggccrd.c from the vstudio project.
-  Updated "libpng14" to "libpng15" in the visualc71 project.
-  Enabled the strip16 tests in pngvalid.`
-  Don't display test results (except PASS/FAIL) when running "make test".
-    Instead put them in pngtest-log.txt
-  Added "--with-zprefix=<string>" to configure.ac
-  Updated the prebuilt configuration files to autoconf version 2.68
-
-Version 1.5.0beta58 [December 19, 2010]
-  Fixed interlace image handling and add test cases (John Bowler)
-  Fixed the clean rule in Makefile.am to remove pngtest-log.txt
-  Made minor changes to work around warnings in gcc 3.4
-
-Version 1.5.0rc01 [December 27, 2010]
-  No changes.
-
-Version 1.5.0rc02 [December 27, 2010]
-  Eliminated references to the scripts/*.def files in project/visualc71.
-
-Version 1.5.0rc03 [December 28, 2010]
-  Eliminated scripts/*.def and revised Makefile.am accordingly
-
-Version 1.5.0rc04 [December 29, 2010]
-  Fixed bug in background transformation handling in pngrtran.c (it was
-    looking for the flag in png_ptr->transformations instead of in
-    png_ptr->flags) (David Raymond).
-
-Version 1.5.0rc05 [December 31, 2010]
-  Fixed typo in a comment in CMakeLists.txt (libpng14 => libpng15) (Cosmin)
-
-Version 1.5.0rc06 [January 4, 2011]
-  Changed the new configure option "zprefix=string" to "zlib-prefix=string"
-
-Version 1.5.0rc07 [January 4, 2011]
-  Updated copyright year.
-
-Version 1.5.0 [January 6, 2011]
-  No changes.
-
-version 1.5.1beta01 [January 8, 2011]
-  Added description of png_set_crc_action() to the manual.
-  Added a note in the manual that the type of the iCCP profile was changed
-    from png_charpp to png_bytepp in png_get_iCCP().  This change happened
-    in version 1.5.0beta36 but is not noted in the CHANGES.  Similarly,
-    it was changed from png_charpp to png_const_bytepp in png_set_iCCP().
-  Ensure that png_rgb_to_gray ignores palette mapped images, if libpng
-    internally happens to call it with one, and fixed a failure to handle
-    palette mapped images correctly.  This fixes CVE-2690.
-
-Version 1.5.1beta02 [January 14, 2011]
-  Fixed a bug in handling of interlaced images (bero at arklinux.org).
-  Updated CMakeLists.txt (Clifford Yapp)
-
-Version 1.5.1beta03 [January 14, 2011]
-  Fixed typecasting of some png_debug() statements (Cosmin)
-
-Version 1.5.1beta04 [January 16, 2011]
-  Updated documentation of png_set|get_tRNS() (Thomas Klausner).
-  Mentioned in the documentation that applications must #include "zlib.h"
-    if they need access to anything in zlib.h, and that a number of
-    macros such as png_memset() are no longer accessible by applications.
-  Corrected pngvalid gamma test "sample" function to access all of the color
-    samples of each pixel, instead of sampling the red channel three times.
-  Prefixed variable names index, div, exp, gamma with "png_" to avoid "shadow"
-    warnings, and (mistakenly) changed png_exp() to exp().
-
-Version 1.5.1beta05 [January 16, 2011]
-  Changed variable names png_index, png_div, png_exp, and png_gamma to
-    char_index, divisor, exp_b10, and gamma_val, respectively, and
-    changed exp() back to png_exp().
-
-Version 1.5.1beta06 [January 20, 2011]
-  Prevent png_push_crc_skip() from hanging while reading an unknown chunk
-    or an over-large compressed zTXt chunk with the progressive reader.
-  Eliminated more GCC "shadow" warnings.
-  Revised png_fixed() in png.c to avoid compiler warning about reaching the
-    end without returning anything.
-
-Version 1.5.1beta07 [January 22, 2011]
-  In the manual, describe the png_get_IHDR() arguments in the correct order.
-  Added const_png_structp and const_png_infop types, and used them in
-    prototypes for most png_get_*() functions.
-
-Version 1.5.1beta08 [January 23, 2011]
-  Added png_get_io_chunk_type() and deprecated png_get_io_chunk_name()
-  Added synopses for the IO_STATE functions and other missing synopses
-    to the manual. Removed the synopses from libpngpf.3 because they
-    were out of date and no longer useful.  Better information can be
-    obtained by reading the prototypes and comments in pngpriv.h
-  Attempted to fix cpp on Solaris with S. Studio 12 cc, fix build
-    Added a make macro DFNCPP that is a CPP that will accept the tokens in
-    a .dfn file and adds configure stuff to test for such a CPP.  ./configure
-    should fail if one is not available.
-  Corrected const_png_ in png.h to png_const_ to avoid polluting the namespace.
-  Added png_get_current_row_number and png_get_current_pass_number for the
-    benefit of the user transform callback.
-  Added png_process_data_pause and png_process_data_skip for the benefit of
-    progressive readers that need to stop data processing or want to optimize
-    skipping of unread data (e.g., if the reader marks a chunk to be skipped.)
-
-Version 1.5.1beta09 [January 24, 2011]
-  Enhanced pngvalid, corrected an error in gray_to_rgb, corrected doc error.
-    pngvalid contains tests of transforms, which tests are currently disabled
-    because they are incompletely tested.  gray_to_rgb was failing to expand
-    the bit depth for smaller bit depth images; this seems to be a long
-    standing error and resulted, apparently, in invalid output
-    (CVE-2011-0408, CERT VU#643140).  The documentation did not accurately
-    describe what libpng really does when converting RGB to gray.
-
-Version 1.5.1beta10 [January 27, 2010]
-  Fixed incorrect examples of callback prototypes in the manual, that were
-    introduced in libpng-1.0.0.
-  In addition the order of the png_get_uint macros with respect to the
-    relevant function definitions has been reversed.  This helps the
-    preprocessing of the symbol files be more robust.  Furthermore, the
-    symbol file preprocessing now uses -DPNG_NO_USE_READ_MACROS even when
-    the library may actually be built with PNG_USE_READ_MACROS; this stops
-    the read macros interfering with the symbol file format.
-  Made the manual, synopses, and function prototypes use the function
-    argument names file_gamma, int_file_gamma, and srgb_intent consistently.
-
-Version 1.5.1beta11 [January 28, 2011]
-  Changed PNG_UNUSED from "param=param;" to "{if(param){}}".
-  Corrected local variable type in new API png_process_data_skip()
-    The type was self-evidently incorrect but only causes problems on 64-bit
-    architectures.
-  Added transform tests to pngvalid and simplified the arguments.
-
-Version 1.5.1rc01 [January 29, 2011]
-  No changes.
-
-Version 1.5.1rc02 [January 31, 2011]
-  Added a request in the manual that applications do not use "png_" or
-    "PNG_" to begin any of their own symbols.
-  Changed PNG_UNUSED to "(void)param;" and updated the commentary in pngpriv.h
-
-Version 1.5.1 [February 3, 2011]
-  No changes.
-
-Version 1.5.2beta01 [February 13, 2011]
-  More -Wshadow fixes for older gcc compilers.  Older gcc versions apparently
-    check formal parameters names in function declarations (as well as
-    definitions) to see if they match a name in the global namespace.
-  Revised PNG_EXPORTA macro to not use an empty parameter, to accommodate the
-    old VisualC++ preprocessor.
-  Turned on interlace handling in png_read_png().
-  Fixed gcc pendantic warnings.
-  Handle longjmp in Cygwin.
-  Fixed png_get_current_row_number() in the interlaced case.
-  Cleaned up ALPHA flags and transformations.
-  Implemented expansion to 16 bits.
-
-Version 1.5.2beta02 [February 19, 2011]
-  Fixed mistake in the descriptions of user read_transform and write_transform
-    function prototypes in the manual.  The row_info struct is png_row_infop.
-  Reverted png_get_current_row_number() to previous (1.5.2beta01) behavior.
-  Corrected png_get_current_row_number documentation
-  Fixed the read/write row callback documentation.
-    This documents the current behavior, where the callback is called after
-    every row with information pertaining to the next row.
-
-Version 1.5.2beta03 [March 3, 2011]
-  Fixed scripts/makefile.vcwin32
-  Updated contrib/pngsuite/README to add the word "modify".
-  Define PNG_ALLOCATED to blank when _MSC_VER<1300.
-
-Version 1.5.2rc01 [March 19, 2011]
-  Define remaining attributes to blank when MSC_VER<1300.
-  ifdef out mask arrays in pngread.c when interlacing is not supported.
-
-Version 1.5.2rc02 [March 22, 2011]
-  Added a hint to try CPP=/bin/cpp if "cpp -E" fails in scripts/pnglibconf.mak
-    and in contrib/pngminim/*/makefile, eg., on SunOS 5.10, and removed "strip"
-    from the makefiles.
-  Fixed a bug (present since libpng-1.0.7) that makes png_handle_sPLT() fail
-    to compile when PNG_NO_POINTER_INDEXING is defined (Chubanov Kirill)
-
-Version 1.5.2rc03 [March 24, 2011]
-  Don't include standard header files in png.h while building the symbol table,
-    to avoid cpp failure on SunOS (introduced PNG_BUILDING_SYMBOL_TABLE macro).
-
-Version 1.5.2 [March 31, 2011]
-  No changes.
-
-Version 1.5.3beta01 [April 1, 2011]
-  Re-initialize the zlib compressor before compressing non-IDAT chunks.
-  Added API functions (png_set_text_compression_level() and four others) to
-    set parameters for zlib compression of non-IDAT chunks.
-
-Version 1.5.3beta02 [April 3, 2011]
-  Updated scripts/symbols.def with new API functions.
-  Only compile the new zlib re-initializing code when text or iCCP is
-    supported, using PNG_WRITE_COMPRESSED_TEXT_SUPPORTED macro.
-  Improved the optimization of the zlib CMF byte (see libpng-1.2.6beta03).
-  Optimize the zlib CMF byte in non-IDAT compressed chunks
-
-Version 1.5.3beta03 [April 16, 2011]
-  Fixed gcc -ansi -pedantic compile. A strict ANSI system does not have
-    snprintf, and the "__STRICT_ANSI__" detects that condition more reliably
-    than __STDC__ (John Bowler).
-  Removed the PNG_PTR_NORETURN attribute because it too dangerous. It tells
-    the compiler that a user supplied callback (the error handler) does not
-    return, yet there is no guarantee in practice that the application code
-    will correctly implement the error handler because the compiler only
-    issues a warning if there is a mistake (John Bowler).
-  Removed the no-longer-used PNG_DEPSTRUCT macro.
-  Updated the zlib version to 1.2.5 in the VStudio project.
-  Fixed 64-bit builds where png_uint_32 is smaller than png_size_t in
-    pngwutil.c (John Bowler).
-  Fixed bug with stripping the filler or alpha channel when writing, that
-    was introduced in libpng-1.5.2beta01 (bug report by Andrew Church).
-
-Version 1.5.3beta04 [April 27, 2011]
-  Updated pngtest.png with the new zlib CMF optimization.
-  Cleaned up conditional compilation code and of background/gamma handling
-    Internal changes only except a new option to avoid compiling the
-    png_build_grayscale_palette API (which is not used at all internally.)
-    The main change is to move the transform tests (READ_TRANSFORMS,
-    WRITE_TRANSFORMS) up one level to the caller of the APIs.  This avoids
-    calls to spurious functions if all transforms are disabled and slightly
-    simplifies those functions.  Pngvalid modified to handle this.
-    A minor change is to stop the strip_16 and expand_16 interfaces from
-    disabling each other; this allows the future alpha premultiplication
-    code to use 16-bit intermediate values while still producing 8-bit output.
-    png_do_background and png_do_gamma have been simplified to take a single
-    pointer to the png_struct rather than pointers to every item required
-    from the png_struct. This makes no practical difference to the internal
-    code.
-  A serious bug in the pngvalid internal routine 'standard_display_init' has
-    been fixed - this failed to initialize the red channel and accidentally
-    initialized the alpha channel twice.
-  Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
-    avoid a possible clash with the png_jmpbuf macro on some platforms.
-
-Version 1.5.3beta05 [May 6, 2011]
-  Added the "_POSIX_SOURCE" feature test macro to ensure libpng sees the
-    correct API. _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and
-    pngvalid.c to ensure that POSIX conformant systems disable non-POSIX APIs.
-  Removed png_snprintf and added formatted warning messages.  This change adds
-    internal APIs to allow png_warning messages to have parameters without
-    requiring the host OS to implement snprintf.  As a side effect the
-    dependency of the tIME-supporting RFC1132 code on stdio is removed and
-    PNG_NO_WARNINGS does actually work now.
-  Pass "" instead of '\0' to png_default_error() in png_err().  This mistake
-    was introduced in libpng-1.2.20beta01.  This fixes CVE-2011-2691.
-  Added PNG_WRITE_OPTIMIZE_CMF_SUPPORTED macro to make the zlib "CMF" byte
-    optimization configureable.
-  IDAT compression failed if preceded by a compressed text chunk (bug
-    introduced in libpng-1.5.3beta01-02).  This was because the attempt to
-    reset the zlib stream in png_write_IDAT happened after the first IDAT
-    chunk had been deflated - much too late.  In this change internal
-    functions were added to claim/release the z_stream and, hopefully, make
-    the code more robust.  Also deflateEnd checking is added - previously
-    libpng would ignore an error at the end of the stream.
-
-Version 1.5.3beta06 [May 8, 2011]
-  Removed the -D_ALL_SOURCE from definitions for AIX in CMakeLists.txt
-  Implemented premultiplied alpha support: png_set_alpha_mode API
-
-Version 1.5.3beta07 [May 11, 2011]
-  Added expand_16 support to the high level interface.
-  Added named value and 'flag' gamma support to png_set_gamma.  Made a minor
-    change from the previous (unreleased) ABI/API to hide the exact value used
-    for Macs - it's not a good idea to embed this in the ABI!
-  Moved macro definitions for PNG_HAVE_IHDR, PNG_HAVE_PLTE, and PNG_AFTER_IDAT
-    from pngpriv.h to png.h because they must be visible to applications
-    that call png_set_unknown_chunks().
-  Check for up->location !PNG_AFTER_IDAT when writing unknown chunks
-    before IDAT.
-
-Version 1.5.3beta08 [May 16, 2011]
-  Improved "pngvalid --speed" to exclude more of pngvalid from the time.
-  Documented png_set_alpha_mode(), other changes in libpng.3/libpng-manual.txt
-  The cHRM chunk now sets the defaults for png_set_rgb_to_gray() (when negative
-    parameters are supplied by the caller), while in the absence of cHRM
-    sRGB/Rec 709 values are still used.  This introduced a divide-by-zero
-    bug in png_handle_cHRM().
-  The bKGD chunk no longer overwrites the background value set by
-    png_set_background(), allowing the latter to be used before the file
-    header is read. It never performed any useful function to override
-    the default anyway.
-  Added memory overwrite and palette image checks to pngvalid.c
-    Previously palette image code was poorly checked. Since the transformation
-    code has a special palette path in most cases this was a severe weakness.
-  Minor cleanup and some extra checking in pngrutil.c and pngrtran.c. When
-    expanding an indexed image, always expand to RGBA if transparency is
-    present.
-
-Version 1.5.3beta09 [May 17, 2011]
-  Reversed earlier 1.5.3 change of transformation order; move png_expand_16
-    back where it was.  The change doesn't work because it requires 16-bit
-    gamma tables when the code only generates 8-bit ones.  This fails
-    silently; the libpng code just doesn't do any gamma correction.  Moving
-    the tests back leaves the old, inaccurate, 8-bit gamma calculations, but
-    these are clearly better than none!
-
-Version 1.5.3beta10 [May 20, 2011]
-
-  png_set_background() and png_expand_16() did not work together correctly.
-    This problem is present in 1.5.2; if png_set_background is called with
-    need_expand false and the matching 16 bit color libpng erroneously just
-    treats it as an 8-bit color because of where png_do_expand_16 is in the
-    transform list.  This simple fix reduces the supplied colour to 8-bits,
-    so it gets smashed, but this is better than the current behavior.
-  Added tests for expand16, more fixes for palette image tests to pngvalid.
-    Corrects the code for palette image tests and disables attempts to
-    validate palette colors.
-
-Version 1.5.3rc01 [June 3, 2011]
-  No changes.
-
-Version 1.5.3rc02 [June 8, 2011]
-  Fixed uninitialized memory read in png_format_buffer() (Bug report by
-    Frank Busse, CVE-2011-2501, related to CVE-2004-0421).
-
-Version 1.5.3beta11 [June 11, 2011]
-  Fixed png_handle_sCAL which is broken in 1.5. This fixes CVE 2011-2692.
-  Added sCAL to pngtest.png
-  Revised documentation about png_set_user_limits() to say that it also affects
-    png writing.
-  Revised handling of png_set_user_limits() so that it can increase the
-    limit beyond the PNG_USER_WIDTH|HEIGHT_MAX; previously it could only
-    reduce it.
-  Make the 16-to-8 scaling accurate. Dividing by 256 with no rounding is
-    wrong (high by one) 25% of the time. Dividing by 257 with rounding is
-    wrong in 128 out of 65536 cases. Getting the right answer all the time
-    without division is easy.
-  Added "_SUPPORTED" to the PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION macro.
-  Added projects/owatcom, an IDE project for OpenWatcom to replace
-    scripts/makefile.watcom.  This project works with OpenWatcom 1.9. The
-    IDE autogenerates appropriate makefiles (libpng.mk) for batch processing.
-    The project is configurable, unlike the Visual Studio project, so long
-    as the developer has an awk.
-  Changed png_set_gAMA to limit the gamma value range so that the inverse
-    of the stored value cannot overflow the fixed point representation,
-    and changed other things OpenWatcom warns about.
-  Revised pngvalid.c to test PNG_ALPHA_MODE_SUPPORTED correctly. This allows
-    pngvalid to build when ALPHA_MODE is not supported, which is required if
-    it is to build on libpng 1.4.
-  Removed string/memory macros that are no longer used and are not
-    necessarily fully supportable, particularly png_strncpy and png_snprintf.
-  Added log option to pngvalid.c and attempted to improve gamma messages.
-
-Version 1.5.3 [omitted]
-  People found the presence of a beta release following an rc release
-    to be confusing; therefore we bump the version to libpng-1.5.4beta01
-    and there will be no libpng-1.5.3 release.
-
-Version 1.5.4beta01 [June 14, 2011]
-  Made it possible to undefine PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-    to get the same (inaccurate) output as libpng-1.5.2 and earlier.
-  Moved definitions of PNG_HAVE_IHDR, PNG_AFTER_IDAT, and PNG_HAVE_PLTE
-    outside of an unknown-chunk block in png.h because they are also
-    needed for other uses.
-
-Version 1.5.4beta02 [June 14, 2011]
-  Fixed and clarified LEGACY 16-to-8 scaling code.
-  Added png_set_chop_16() API, to match inaccurate results from previous
-    libpng versions.
-  Removed the ACCURATE and LEGACY options (they are no longer useable)
-  Use the old scaling method for background if png_set_chop_16() was
-    called.
-  Made png_set_chop_16() API removeable by disabling PNG_CHOP_16_TO_8_SUPPORTED
-
-Version 1.5.4beta03 [June 15, 2011]
-  Fixed a problem in png_do_expand_palette() exposed by optimization in
-    1.5.3beta06
-  Also removed a spurious and confusing "trans" member ("trans") from png_info.
-  The palette expand optimization prevented expansion to an intermediate RGBA
-    form if tRNS was present but alpha was marked to be stripped; this exposed
-    a check for tRNS in png_do_expand_palette() which is inconsistent with the
-    code elsewhere in libpng.
-  Correction to the expand_16 code; removed extra instance of
-    png_set_scale_16_to_8 from pngpriv.h
-
-Version 1.5.4beta04 [June 16, 2011]
-  Added a missing "#ifdef PNG_READ_BACKGROUND_SUPPORTED/#endif" in pngrtran.c
-  Added PNG_TRANSFORM_CHOP_16 to the high-level read transforms.
-  Made PNG_READ_16_TO_8_ACCURATE_SCALE configurable again.  If this is
-    not enabled, png_set_strip_16() and png_do_scale_16_to_8() aren't built.
-  Revised contrib/visupng, gregbook, and pngminim to demonstrate chop_16_to_8
-
-Version 1.5.4beta05 [June 16, 2011]
-  Renamed png_set_strip_16() to png_set_scale_16() and renamed
-    png_set_chop_16() to png_set_strip(16) in an attempt to minimize the
-    behavior changes between libpng14 and libpng15.
-
-Version 1.5.4beta06 [June 18, 2011]
-  Fixed new bug that was causing both strip_16 and scale_16 to be applied.
-
-Version 1.5.4beta07 [June 19, 2011]
-  Fixed pngvalid, simplified macros, added checking for 0 in sCAL.
-    The ACCURATE scale macro is no longer defined in 1.5 - call the
-    png_scale_16_to_8 API.  Made sure that PNG_READ_16_TO_8 is still defined
-    if the png_strip_16_to_8 API is present.  png_check_fp_number now
-    maintains some state so that positive, negative and zero values are
-    identified.  sCAL uses these to be strictly spec conformant.
-
-Version 1.5.4beta08 [June 23, 2011]
-  Fixed pngvalid if ACCURATE_SCALE is defined.
-  Updated scripts/pnglibconf.h.prebuilt.
-
-Version 1.5.4rc01 [June 30, 2011]
-  Define PNG_ALLOCATED to "restrict" only if MSC_VER >= 1400.
-
-Version 1.5.4 [July 7, 2011]
-  No changes.
-
-Version 1.5.5beta01 [July 13, 2011]
-  Fixed some typos and made other minor changes in the manual.
-  Updated contrib/pngminus/makefile.std (Samuli Souminen)
-
-Version 1.5.5beta02 [July 14, 2011]
-  Revised Makefile.am and Makefile.in to look in the right directory for
-    pnglibconf.h.prebuilt
-
-Version 1.5.5beta03 [July 27, 2011]
-  Enabled compilation with g++ compiler.  This compiler does not recognize
-    the file extension, so it always compiles with C++ rules.  Made minor
-    changes to pngrutil.c to cast results where C++ expects it but C does not.
-  Minor editing of libpng.3 and libpng-manual.txt.
-
-Version 1.5.5beta04 [July 29, 2011]
-  Revised CMakeLists.txt (Clifford Yapp)
-  Updated commentary about the png_rgb_to_gray() default coefficients
-    in the manual and in pngrtran.c
-
-Version 1.5.5beta05 [August 17, 2011]
-  Prevent unexpected API exports from non-libpng DLLs on Windows.  The "_DLL"
-    is removed from the test of whether a DLL is being built (this erroneously
-    caused the libpng APIs to be marked as DLL exports in static builds under
-    Microsoft Visual Studio).  Almost all of the libpng building configuration
-    is moved from pngconf.h to pngpriv.h, but PNG_DLL_EXPORT remains in
-    pngconf.h, though, so that it is colocated with the import definition (it
-    is no longer used anywhere in the installed headers).  The VStudio project
-    definitions have been cleaned up: "_USRDLL" has been removed from the
-    static library builds (this was incorrect), and PNG_USE_DLL has been added
-    to pngvalid to test the functionality (pngtest does not supply it,
-    deliberately).  The spurious "_EXPORTS" has been removed from the
-    libpng build (all these errors were a result of copy/paste between project
-    configurations.)
-  Added new types and internal functions for CIE RGB end point handling to
-    pngpriv.h (functions yet to be implemented).
-
-Version 1.5.5beta06 [August 26, 2011]
-  Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set in CMakeLists.txt
-    (Clifford Yap)
-  Fixes to rgb_to_gray and cHRM XYZ APIs (John Bowler):
-    The rgb_to_gray code had errors when combined with gamma correction.
-    Some pixels were treated as true grey when they weren't and such pixels
-    and true grey ones were not gamma corrected (the original value of the
-    red component was used instead).  APIs to get and set cHRM using color
-    space end points have been added and the rgb_to_gray code that defaults
-    based on cHRM, and the divide-by-zero bug in png_handle_cHRM (CERT
-    VU#477046, CVE-2011-3328, introduced in 1.5.4) have been corrected.
-  A considerable number of tests has been added to pngvalid for the
-    rgb_to_gray transform.
-  Arithmetic errors in rgb_to_gray whereby the calculated gray value was
-    truncated to the bit depth rather than rounded have been fixed except in
-    the 8-bit non-gamma-corrected case (where consistency seems more important
-    than correctness.)  The code still has considerable inaccuracies in the
-    8-bit case because 8-bit linear arithmetic is used.
-
-Version 1.5.5beta07 [September 7, 2011]
-  Added "$(ARCH)" option to makefile.darwin
-  Added SunOS support to configure.ac and Makefile.am
-  Changed png_chunk_benign_error() to png_warning() in png.c, in
-    png_XYZ_from_xy_checked().
-
-Version 1.5.5beta08 [September 10, 2011]
-  Fixed 64-bit compilation errors (gcc). The errors fixed relate
-    to conditions where types that are 32 bits in the GCC 32-bit
-    world (uLong and png_size_t) become 64 bits in the 64-bit
-    world.  This produces potential truncation errors which the
-    compiler correctly flags.
-  Relocated new HAVE_SOLARIS_LD definition in configure.ac
-  Constant changes for 64-bit compatibility (removal of L suffixes). The
-    16-bit cases still use "L" as we don't have a 16-bit test system.
-
-Version 1.5.5rc01 [September 15, 2011]
-  Removed "L" suffixes in pngpriv.h
-
-Version 1.5.5 [September 22, 2011]
-  No changes.
-
-Version 1.5.6beta01 [September 22, 2011]
-  Fixed some 64-bit type conversion warnings in pngrtran.c
-  Moved row_info from png_struct to a local variable.
-  The various interlace mask arrays have been made into arrays of
-    bytes and made PNG_CONST and static (previously some arrays were
-    marked PNG_CONST and some weren't).
-  Additional checks have been added to the transform code to validate the
-    pixel depths after the transforms on both read and write.
-  Removed some redundant code from pngwrite.c, in png_destroy_write_struct().
-  Changed chunk reading/writing code to use png_uint_32 instead of png_byte[4].
-    This removes the need to allocate temporary strings for chunk names on
-    the stack in the read/write code.  Unknown chunk handling still uses the
-    string form because this is exposed in the API.
-
-Version 1.5.6beta02 [September 26, 2011]
-  Added a note in the manual the png_read_update_info() must be called only
-    once with a particular info_ptr.
-  Fixed a typo in the definition of the new PNG_STRING_FROM_CHUNK(s,c) macro.
-
-Version 1.5.6beta03 [September 28, 2011]
-  Revised test-pngtest.sh to report FAIL when pngtest fails.
-  Added "--strict" option to pngtest, to report FAIL when the failure is
-    only because the resulting valid files are different.
-  Revised CMakeLists.txt to work with mingw and removed some material from
-    CMakeLists.txt that is no longer useful in libpng-1.5.
-
-Version 1.5.6beta04 [October 5, 2011]
-  Fixed typo in Makefile.in and Makefile.am ("-M Wl" should be "-M -Wl")."
-
-Version 1.5.6beta05 [October 12, 2011]
-  Speed up png_combine_row() for interlaced images. This reduces the generality
-    of the code, allowing it to be optimized for Adam7 interlace.  The masks
-    passed to png_combine_row() are now generated internally, avoiding
-    some code duplication and localizing the interlace handling somewhat.
-  Align png_struct::row_buf - previously it was always unaligned, caused by
-    a bug in the code that attempted to align it; the code needs to subtract
-    one from the pointer to take account of the filter byte prepended to
-    each row.
-  Optimized png_combine_row() when rows are aligned. This gains a small
-    percentage for 16-bit and 32-bit pixels in the typical case where the
-    output row buffers are appropriately aligned. The optimization was not
-    previously possible because the png_struct buffer was always misaligned.
-  Fixed bug in png_write_chunk_header() debug print, introduced in 1.5.6beta01.
-
-Version 1.5.6beta06 [October 17, 2011]
-  Removed two redundant tests for unitialized row.
-  Fixed a relatively harmless memory overwrite in compressed text writing
-    with a 1 byte zlib buffer.
-  Add ability to call png_read_update_info multiple times to pngvalid.c.
-  Fixes for multiple calls to png_read_update_info. These fixes attend to
-    most of the errors revealed in pngvalid, however doing the gamma work
-    twice results in inaccuracies that can't be easily fixed.  There is now
-    a warning in the code if this is going to happen.
-  Turned on multiple png_read_update_info in pngvalid transform tests.
-  Prevent libpng from overwriting unused bits at the end of the image when
-    it is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would
-    overwrite the partial byte at the end of each row if the row width was not
-    an exact multiple of 8 bits and the image is not interlaced.
-
-Version 1.5.6beta07 [October 21, 2011]
-  Made png_ptr->prev_row an aligned pointer into png_ptr->big_prev_row
-    (Mans Rullgard).
-
-Version 1.5.6rc01 [October 26, 2011]
-  Changed misleading "Missing PLTE before cHRM" warning to "Out of place cHRM"
-
-Version 1.5.6rc02 [October 27, 2011]
-  Added LSR() macro to defend against buggy compilers that evaluate non-taken
-    code branches and complain about out-of-range shifts.
-
-Version 1.5.6rc03 [October 28, 2011]
-  Renamed the LSR() macro to PNG_LSR() and added PNG_LSL() macro.
-  Fixed compiler warnings with Intel and MSYS compilers. The logical shift
-    fix for Microsoft Visual C is required by other compilers, so this
-    enables that fix for all compilers when using compile-time constants.
-    Under MSYS 'byte' is a name declared in a system header file, so we
-    changed the name of a local variable to avoid the warnings that result.
-  Added #define PNG_ALIGN_TYPE PNG_ALIGN_NONE to contrib/pngminim/*/pngusr.h
-
-Version 1.5.6 [November 3, 2011]
-  No changes.
-
-Version 1.5.7beta01 [November 4, 2011]
-  Added support for ARM processor, when decoding all PNG up-filtered rows
-    and any other-filtered rows with 3 or 4 bytes per pixel (Mans Rullgard).
-  Fixed bug in pngvalid on early allocation failure; fixed type cast in
-    pngmem.c; pngvalid would attempt to call png_error() if the allocation
-    of a png_struct or png_info failed. This would probably have led to a
-    crash.  The pngmem.c implementation of png_malloc() included a cast
-    to png_size_t which would fail on large allocations on 16-bit systems.
-  Fix for the preprocessor of the Intel C compiler. The preprocessor
-    splits adjacent @ signs with a space; this changes the concatentation
-    token from @-@-@ to PNG_JOIN; that should work with all compiler
-    preprocessors.
-  Paeth filter speed improvements from work by Siarhei Siamashka. This
-    changes the 'Paeth' reconstruction function to improve the GCC code
-    generation on x86. The changes are only part of the suggested ones;
-    just the changes that definitely improve speed and remain simple.
-    The changes also slightly increase the clarity of the code.
-
-Version 1.5.7beta02 [November 11, 2011]
-  Check compression_type parameter in png_get_iCCP and remove spurious
-    casts. The compression_type parameter is always assigned to, so must
-    be non-NULL. The cast of the profile length potentially truncated the
-    value unnecessarily on a 16-bit int system, so the cast of the (byte)
-    compression type to (int) is specified by ANSI-C anyway.
-  Fixed FP division by zero in pngvalid.c; the 'test_pixel' code left
-    the sBIT fields in the test pixel as 0, which resulted in a floating
-    point division by zero which was irrelevant but causes systems where
-    FP exceptions cause a crash. Added code to pngvalid to turn on FP
-    exceptions if the appropriate glibc support is there to ensure this is
-    tested in the future.
-  Updated scripts/pnglibconf.mak and scripts/makefile.std to handle the
-    new PNG_JOIN macro.
-  Added versioning to pnglibconf.h comments.
-  Simplified read/write API initial version; basic read/write tested on
-    a variety of images, limited documentation (in the header file.)
-  Installed more accurate linear to sRGB conversion tables. The slightly
-    modified tables reduce the number of 16-bit values that
-    convert to an off-by-one 8-bit value.  The "makesRGB.c" code that was used
-    to generate the tables is now in a contrib/sRGBtables sub-directory.
-
-Version 1.5.7beta03 [November 17, 2011]
-  Removed PNG_CONST from the sRGB table declarations in pngpriv.h and png.c
-  Added run-time detection of NEON support.
-  Added contrib/libtests; includes simplified API test and timing test and
-    a color conversion utility for rapid checking of failed 'pngstest' results.
-  Multiple transform bug fixes plus a work-round for double gamma correction.
-    libpng does not support more than one transform that requires linear data
-    at once - if this is tried typically the results is double gamma
-    correction. Since the simplified APIs can need rgb to gray combined with
-    a compose operation it is necessary to do one of these outside the main
-    libpng transform code. This check-in also contains fixes to various bugs
-    in the simplified APIs themselves and to some bugs in compose and rgb to
-    gray (on palette) itself.
-  Fixes for C++ compilation using g++ When libpng source is compiled
-    using g++. The compiler imposes C++ rules on the C source; thus it
-    is desireable to make the source work with either C or C++ rules
-    without throwing away useful error information.  This change adds
-    png_voidcast to allow C semantic (void*) cases or the corresponding
-    C++ static_cast operation, as appropriate.
-  Added --noexecstack to assembler file compilation. GCC does not set
-    this on assembler compilation, even though it does on C compilation.
-    This creates security issues if assembler code is enabled; the
-    work-around is to set it by default in the flags for $(CCAS)
-  Work around compilers that don't support declaration of const data. Some
-    compilers fault 'extern const' data declarations (because the data is
-    not initialized); this turns on const-ness only for compilers where
-    this is known to work.
-
-Version 1.5.7beta04 [November 17, 2011]
-  Since the gcc driver does not recognize the --noexecstack flag, we must
-    use the -Wa prefix to have it passed through to the assembler.
-    Also removed a duplicate setting of this flag.
-  Added files that were omitted from the libpng-1.5.7beta03 zip distribution.
-
-Version 1.5.7beta05 [November 25, 2011]
-  Removed "zTXt" from warning in generic chunk decompression function.
-  Validate time settings passed to png_set_tIME() and png_convert_to_rfc1123()
-    (Frank Busse). Note: This prevented CVE-2015-7981 from affecting
-    libpng-1.5.7 and later.
-  Added MINGW support to CMakeLists.txt
-  Reject invalid compression flag or method when reading the iTXt chunk.
-  Backed out 'simplified' API changes. The API seems too complex and there
-    is a lack of consensus or enthusiasm for the proposals.  The API also
-    reveals significant bugs inside libpng (double gamma correction and the
-    known bug of being unable to retrieve a corrected palette). It seems
-    better to wait until the bugs, at least, are corrected.
-  Moved pngvalid.c into contrib/libtests
-  Rebuilt Makefile.in, configure, etc., with autoconf-2.68
-
-Version 1.5.7rc01 [December 1, 2011]
-  Replaced an "#if" with "#ifdef" in pngrtran.c
-  Revised #if PNG_DO_BC block in png.c (use #ifdef and add #else)
-
-Version 1.5.7rc02 [December 5, 2011]
-  Revised project files and contrib/pngvalid/pngvalid.c to account for
-    the relocation of pngvalid into contrib/libtests.
-  Revised pngconf.h to use " __declspec(restrict)" only when MSC_VER >= 1400,
-    as in libpng-1.5.4.
-  Put CRLF line endings in the owatcom project files.
-
-Version 1.5.7rc03 [December 7, 2011]
-  Updated CMakeLists.txt to account for the relocation of pngvalid.c
-
-Version 1.5.7 [December 15, 2011]
-  Minor fixes to pngvalid.c for gcc 4.6.2 compatibility to remove warnings
-    reported by earlier versions.
-  Fixed minor memset/sizeof errors in pngvalid.c.
-
-Version 1.6.0beta01 [December 15, 2011]
-  Removed machine-generated configure files from the GIT repository (they will
-    continue to appear in the tarball distributions and in the libpng15 and
-    earlier GIT branches).
-  Restored the new 'simplified' API, which was started in libpng-1.5.7beta02
-    but later deleted from libpng-1.5.7beta05.
-  Added example programs for the new 'simplified' API.
-  Added ANSI-C (C90) headers and require them, and take advantage of the
-    change. Also fixed some of the projects/* and contrib/* files that needed
-    updates for libpng16 and the move of pngvalid.c.
-    With this change the required ANSI-C header files are assumed to exist: the
-    implementation must provide float.h, limits.h, stdarg.h and stddef.h and
-    libpng relies on limits.h and stddef.h existing and behaving as defined
-    (the other two required headers aren't used).  Non-ANSI systems that don't
-    have stddef.h or limits.h will have to provide an appropriate fake
-    containing the relevant types and #defines.
-  Dropped support for 16-bit platforms. The use of FAR/far has been eliminated
-    and the definition of png_alloc_size_t is now controlled by a flag so
-    that 'small size_t' systems can select it if necessary.  Libpng 1.6 may
-    not currently work on such systems -- it seems likely that it will
-    ask 'malloc' for more than 65535 bytes with any image that has a
-    sufficiently large row size (rather than simply failing to read such
-    images).
-  New tools directory containing tools used to generate libpng code.
-  Fixed race conditions in parallel make builds. With higher degrees of
-    parallelism during 'make' the use of the same temporary file names such
-    as 'dfn*' can result in a race where a temporary file from one arm of the
-    build is deleted or overwritten in another arm.  This changes the
-    temporary files for suffix rules to always use $* and ensures that the
-    non-suffix rules use unique file names.
-
-Version 1.6.0beta02 [December 21, 2011]
-  Correct configure builds where build and source directories are separate.
-    The include path of 'config.h' was erroneously made relative in pngvalid.c
-    in libpng 1.5.7.
-
-Version 1.6.0beta03 [December 22, 2011]
-  Start-up code size improvements, error handler flexibility. These changes
-    alter how the tricky allocation of the initial png_struct and png_info
-    structures are handled. png_info is now handled in pretty much the same
-    way as everything else, except that the allocations handle NULL return
-    silently.  png_struct is changed in a similar way on allocation and on
-    deallocation a 'safety' error handler is put in place (which should never
-    be required).  The error handler itself is changed to permit mismatches
-    in the application and libpng error buffer size; however, this means a
-    silent change to the API to return the jmp_buf if the size doesn't match
-    the size from the libpng compilation; libpng now allocates the memory and
-    this may fail.  Overall these changes result in slight code size
-    reductions; however, this is a reduction in code that is always executed
-    so is particularly valuable.  Overall on a 64-bit system the libpng DLL
-    decreases in code size by 1733 bytes.  pngerror.o increases in size by
-    about 465 bytes because of the new functionality.
-  Added png_convert_to_rfc1123_buffer() and deprecated png_convert_to_rfc1123()
-    to avoid including a spurious buffer in the png_struct.
-
-Version 1.6.0beta04 [December 30, 2011]
-  Regenerated configure scripts with automake-1.11.2
-  Eliminated png_info_destroy(). It is now used only in png.c and only calls
-    one other internal function and memset().
-  Enabled png_get_sCAL_fixed() if floating point APIs are enabled. Previously
-    it was disabled whenever internal fixed point arithmetic was selected,
-    which meant it didn't exist even on systems where FP was available but not
-    preferred.
-  Added pngvalid.c compile time checks for const APIs.
-  Implemented 'restrict' for png_info and png_struct. Because of the way
-    libpng works both png_info and png_struct are always accessed via a
-    single pointer.  This means adding C99 'restrict' to the pointer gives
-    the compiler some opportunity to optimize the code.  This change allows
-    that.
-  Moved AC_MSG_CHECKING([if libraries can be versioned]) later to the proper
-    location in configure.ac (Gilles Espinasse).
-  Changed png_memcpy to C assignment where appropriate. Changed all those
-    uses of png_memcpy that were doing a simple assignment to assignments
-    (all those cases where the thing being copied is a non-array C L-value).
-  Added some error checking to png_set_*() routines.
-  Removed the reference to the non-exported function png_memcpy() from
-    example.c.
-  Fixed the Visual C 64-bit build - it requires jmp_buf to be aligned, but
-    it had become misaligned.
-  Revised contrib/pngminus/pnm2png.c to avoid warnings when png_uint_32
-    and unsigned long are of different sizes.
-
-Version 1.6.0beta05 [January 15, 2012]
-  Updated manual with description of the simplified API (copied from png.h)
-  Fix bug in pngerror.c: some long warnings were being improperly truncated
-    (CVE-2011-3464, bug introduced in libpng-1.5.3beta05).
-
-Version 1.6.0beta06 [January 24, 2012]
-  Added palette support to the simplified APIs. This commit
-    changes some of the macro definitions in png.h, app code
-    may need corresponding changes.
-  Increased the formatted warning buffer to 192 bytes.
-  Added color-map support to simplified API. This is an initial version for
-    review; the documentation has not yet been updated.
-  Fixed Min/GW uninstall to remove libpng.dll.a
-
-Version 1.6.0beta07 [January 28, 2012]
-  Eliminated Intel icc/icl compiler warnings. The Intel (GCC derived)
-    compiler issues slightly different warnings from those issued by the
-    current vesions of GCC. This eliminates those warnings by
-    adding/removing casts and small code rewrites.
-  Updated configure.ac from autoupdate: added --enable-werror option.
-    Also some layout regularization and removal of introduced tab characters
-    (replaced with 3-character indentation).  Obsolete macros identified by
-    autoupdate have been removed; the replacements are all in 2.59 so
-    the pre-req hasn't been changed.  --enable-werror checks for support
-    for -Werror (or the given argument) in the compiler.  This mimics the
-    gcc configure option by allowing -Werror to be turned on safely; without
-    the option the tests written in configure itself fail compilation because
-    they cause compiler warnings.
-  Rewrote autogen.sh to run autoreconf instead of running tools one-by-one.
-  Conditionalize the install rules for MINGW and CYGWIN in CMakeLists.txt and
-    set CMAKE_LIBRARY_OUTPUT_DIRECTORY to "lib" on all platforms (C. Yapp).
-  Freeze libtool files in the 'scripts' directory. This version of autogen.sh
-    attempts to dissuade people from running it when it is not, or should not,
-    be necessary.  In fact, autogen.sh does not work when run in a libpng
-    directory extracted from a tar distribution anymore. You must run it in
-    a GIT clone instead.
-  Added two images to contrib/pngsuite (1-bit and 2-bit transparent grayscale),
-    and renamed three whose names were inconsistent with those in
-    pngsuite/README.txt.
-
-Version 1.6.0beta08 [February 1, 2012]
-  Fixed Image::colormap misalignment in pngstest.c
-  Check libtool/libtoolize version number (2.4.2) in configure.ac
-  Divide test-pngstest.sh into separate pngstest runs for basic and
-    transparent images.
-  Moved automake options to AM_INIT_AUTOMAKE in configure.ac
-  Added color-tests, silent-rules (Not yet implemented in Makefile.am) and
-    version checking to configure.ac
-  Improved pngstest speed by not doing redundant tests and add const to
-    the background parameter of png_image_finish_read. The --background
-    option is now done automagically only when required, so that commandline
-    option no longer exists.
-  Cleaned up pngpriv.h to consistently declare all functions and data.
-    Also eliminated PNG_CONST_DATA, which is apparently not needed but we
-    can't be sure until it is gone.
-  Added symbol prefixing that allows all the libpng external symbols
-    to be prefixed (suggested by Reuben Hawkins).
-  Updated "ftbb*.png" list in the owatcom and vstudio projects.
-  Fixed 'prefix' builds on clean systems. The generation of pngprefix.h
-    should not require itself.
-  Updated INSTALL to explain that autogen.sh must be run in a GIT clone,
-    not in a libpng directory extracted from a tar distribution.
-
-Version 1.6.0beta09 [February 1, 2012]
-  Reverted the prebuilt configure files to libpng-1.6.0beta05 condition.
-
-Version 1.6.0beta10 [February 3, 2012]
-  Added Z_SOLO for zlib-1.2.6+ and correct pngstest tests
-  Updated list of test images in CMakeLists.txt
-  Updated the prebuilt configure files to current condition.
-  Revised INSTALL information about autogen.sh; it works in tar distributions.
-
-Version 1.6.0beta11 [February 16, 2012]
-  Fix character count in pngstest command in projects/owatcom/pngstest.tgt
-  Revised test-pngstest.sh to report PASS/FAIL for each image.
-  Updated documentation about the simplified API.
-  Corrected estimate of error in libpng png_set_rgb_to_gray API.  The API is
-    extremely inaccurate for sRGB conversions because it uses an 8-bit
-    intermediate linear value and it does not use the sRGB transform, so it
-    suffers from the known instability in gamma transforms for values close
-    to 0 (see Poynton).  The net result is that the calculation has a maximum
-    error of 14.99/255; 0.5/255^(1/2.2).  pngstest now uses 15 for the
-    permitted 8-bit error. This may still not be enough because of arithmetic
-    error.
-  Removed some unused arrays (with #ifdef) from png_read_push_finish_row().
-  Fixed a memory overwrite bug in simplified read of RGB PNG with
-    non-linear gamma Also bugs in the error checking in pngread.c and changed
-    quite a lot of the checks in pngstest.c to be correct; either correctly
-    written or not over-optimistic.  The pngstest changes are insufficient to
-    allow all possible RGB transforms to be passed; pngstest cmppixel needs
-    to be rewritten to make it clearer which errors it allows and then changed
-    to permit known inaccuracies.
-  Removed tests for no-longer-used *_EMPTY_PLTE_SUPPORTED from pngstruct.h
-  Fixed fixed/float API export conditionals. 1) If FIXED_POINT or
-    FLOATING_POINT options were switched off, png.h ended up with lone ';'
-    characters.  This is not valid ANSI-C outside a function.  The ';'
-    characters have been moved inside the definition of PNG_FP_EXPORT and
-    PNG_FIXED_EXPORT. 2) If either option was switched off, the declaration
-    of the corresponding functions were completely omitted, even though some
-    of them are still used internally.  The result is still valid, but
-    produces warnings from gcc with some warning options (including -Wall). The
-    fix is to cause png.h to declare the functions with PNG_INTERNAL_FUNCTION
-    when png.h is included from pngpriv.h.
-  Check for invalid palette index while reading paletted PNG.  When one is
-    found, issue a warning and increase png_ptr->num_palette accordingly.
-    Apps are responsible for checking to see if that happened.
-
-Version 1.6.0beta12 [February 18, 2012]
-  Do not increase num_palette on invalid_index.
-  Relocated check for invalid palette index to pngrtran.c, after unpacking
-    the sub-8-bit pixels.
-  Fixed CVE-2011-3026 buffer overrun bug.  This bug was introduced when
-    iCCP chunk support was added at libpng-1.0.6. Deal more correctly with the
-    test on iCCP chunk length. Also removed spurious casts that may hide
-    problems on 16-bit systems.
-
-Version 1.6.0beta13 [February 24, 2012]
-  Eliminated redundant png_push_read_tEXt|zTXt|iTXt|unknown code from
-    pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
-    now that png_ptr->buffer is inaccessible to applications, the special
-    handling is no longer useful.
-  Added PNG_SAFE_LIMITS feature to pnglibconf.dfa, pngpriv.h, and new
-    pngusr.dfa to reset the user limits to safe ones if PNG_SAFE_LIMITS is
-    defined.  To enable, use "CPPFLAGS=-DPNG_SAFE_LIMITS_SUPPORTED=1" on the
-    configure command or put #define PNG_SAFE_LIMITS_SUPPORTED in
-    pnglibconf.h.prebuilt and pnglibconf.h.
-
-Version 1.6.0beta14 [February 27, 2012]
-  Added information about the new limits in the manual.
-  Updated Makefile.in
-
-Version 1.6.0beta15 [March 2, 2012]
-  Removed unused "current_text" members of png_struct and the png_free()
-    of png_ptr->current_text from pngread.c
-  Rewrote pngstest.c for substantial speed improvement.
-  Fixed transparent pixel and 16-bit rgb tests in pngstest and removed a
-    spurious check in pngwrite.c
-  Added PNG_IMAGE_FLAG_FAST for the benefit of applications that store
-    intermediate files, or intermediate in-memory data, while processing
-    image data with the simplified API.  The option makes the files larger
-    but faster to write and read.  pngstest now uses this by default; this
-    can be disabled with the --slow option.
-  Improved pngstest fine tuning of error numbers, new test file generator.
-    The generator generates images that test the full range of sample values,
-    allow the error numbers in pngstest to be tuned and checked.  makepng
-    also allows generation of images with extra chunks, although this is
-    still work-in-progress.
-  Added check for invalid palette index while reading.
-  Fixed some bugs in ICC profile writing. The code should now accept
-    all potentially valid ICC profiles and reject obviously invalid ones.
-    It now uses png_error() to do so rather than casually writing a PNG
-    without the necessary color data.
-  Removed whitespace from the end of lines in all source files and scripts.
-
-Version 1.6.0beta16 [March 6, 2012]
-  Relocated palette-index checking function from pngrutil.c to pngtrans.c
-  Added palette-index checking while writing.
-  Changed png_inflate() and calling routines to avoid overflow problems.
-    This is an intermediate check-in that solves the immediate problems and
-    introduces one performance improvement (avoiding a copy via png_ptr->zbuf.)
-    Further changes will be made to make ICC profile handling more secure.
-  Fixed build warnings (MSVC, GCC, GCC v3). Cygwin GCC with default options
-    declares 'index' as a global, causing a warning if it is used as a local
-    variable.  GCC 64-bit warns about assigning a (size_t) (unsigned 64-bit)
-    to an (int) (signed 32-bit).  MSVC, however, warns about using the
-    unary '-' operator on an unsigned value (even though it is well defined
-    by ANSI-C to be ~x+1).  The padding calculation was changed to use a
-    different method.  Removed the tests on png_ptr->pass.
-  Added contrib/libtests/tarith.c to test internal arithmetic functions from
-    png.c. This is a libpng maintainer program used to validate changes to the
-    internal arithmetic functions.
-  Made read 'inflate' handling like write 'deflate' handling. The read
-    code now claims and releases png_ptr->zstream, like the write code.
-    The bug whereby the progressive reader failed to release the zstream
-    is now fixed, all initialization is delayed, and the code checks for
-    changed parameters on deflate rather than always calling
-    deflatedEnd/deflateInit.
-  Validate the zTXt strings in pngvalid.
-  Added code to validate the windowBits value passed to deflateInit2().
-    If the call to deflateInit2() is wrong a png_warning will be issued
-    (in fact this is harmless, but the PNG data produced may be sub-optimal).
-
-Version 1.6.0beta17 [March 10, 2012]
-  Fixed PNG_LIBPNG_BUILD_BASE_TYPE definition. 
-  Reject all iCCP chunks after the first, even if the first one is invalid.
-  Deflate/inflate was reworked to move common zlib calls into single
-    functions [rw]util.c.  A new shared keyword check routine was also added
-    and the 'zbuf' is no longer allocated on progressive read.  It is now
-    possible to call png_inflate() incrementally.  A warning is no longer
-    issued if the language tag or translated keyword in the iTXt chunk
-    has zero length.
-  If benign errors are disabled use maximum window on ancilliary inflate.
-    This works round a bug introduced in 1.5.4 where compressed ancillary
-    chunks could end up with a too-small windowBits value in the deflate
-    header.
-
-Version 1.6.0beta18 [March 16, 2012]
-  Issue a png_benign_error() instead of png_warning() about bad palette index.
-  In pngtest, treat benign errors as errors if "-strict" is present.
-  Fixed an off-by-one error in the palette index checking function.
-  Fixed a compiler warning under Cygwin (Windows-7, 32-bit system)
-  Revised example.c to put text strings in a temporary character array
-    instead of directly assigning string constants to png_textp members.
-    This avoids compiler warnings when -Wwrite-strings is enabled.
-  Added output flushing to aid debugging under Visual Studio. Unfortunately
-    this is necessary because the VS2010 output window otherwise simply loses
-    the error messages on error (they weren't flushed to the window before
-    the process exited, apparently!)
-  Added configuration support for benign errors and changed the read
-    default. Also changed some warnings in the iCCP and sRGB handling
-    from to benign errors. Configuration now makes read benign
-    errors warnings and write benign errors to errors by default (thus
-    changing the behavior on read).  The simplified API always forces
-    read benign errors to warnings (regardless of the system default, unless
-    this is disabled in which case the simplified API can't be built.)
-
-Version 1.6.0beta19 [March 18, 2012]
-  Work around for duplicate row start calls; added warning messages.
-    This turns on PNG_FLAG_DETECT_UNINITIALIZED to detect app code that
-    fails to call one of the 'start' routines (not enabled in libpng-1.5
-    because it is technically an API change, since it did normally work
-    before.)  It also makes duplicate calls to png_read_start_row (an
-    internal function called at the start of the image read) benign, as
-    they were before changes to use png_inflate_claim. Somehow webkit is
-    causing this to happen; this is probably a mis-feature in the zlib
-    changes so this commit is only a work-round.
-  Removed erroneous setting of DETECT_UNINITIALIZED and added more
-    checks. The code now does a png_error if an attempt is made to do the
-    row initialization twice; this is an application error and it has
-    serious consequences because the transform data in png_struct is
-    changed by each call.
-  Added application error reporting and added chunk names to read
-    benign errors; also added --strict to pngstest - not enabled
-    yet because a warning is produced.
-  Avoid the double gamma correction warning in the simplified API.
-    This allows the --strict option to pass in the pngstest checks
-
-Version 1.6.0beta20 [March 29, 2012]
-  Changed chunk handler warnings into benign errors, incrementally load iCCP
-  Added checksum-icc.c to contrib/tools
-  Prevent PNG_EXPAND+PNG_SHIFT doing the shift twice.
-  Recognize known sRGB ICC profiles while reading; prefer writing the
-    iCCP profile over writing the sRGB chunk, controlled by the
-    PNG_sRGB_PROFILE_CHECKS option.
-  Revised png_set_text_2() to avoid potential memory corruption (fixes
-    CVE-2011-3048, also known as CVE-2012-3425).
-
-Version 1.6.0beta21 [April 27, 2012]
-  Revised scripts/makefile.darwin: use system zlib; remove quotes around
-    architecture list; add missing ppc architecture; add architecture options
-    to shared library link; don't try to create a shared lib based on missing
-    RELEASE variable.
-  Enable png_set_check_for_invalid_index() for both read and write.
-  Removed #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED in pngpriv.h around
-    declaration of png_handle_unknown().
-  Added -lssp_nonshared in a comment in scripts/makefile.freebsd
-    and changed deprecated NOOBJ and NOPROFILE to NO_OBJ and NO_PROFILE.
-
-Version 1.6.0beta22 [May 23, 2012]
-  Removed need for -Wno-cast-align with clang.  clang correctly warns on
-    alignment increasing pointer casts when -Wcast-align is passed. This
-    fixes the cases that clang warns about either by eliminating the
-    casts from png_bytep to png_uint_16p (pngread.c), or, for pngrutil.c
-    where the cast is previously verified or pngstest.c where it is OK, by
-    introducing new png_aligncast macros to do the cast in a way that clang
-    accepts.
-
-Version 1.6.0beta23 [June 6, 2012]
-  Revised CMakeLists.txt to not attempt to make a symlink under mingw.
-  Made fixes for new optimization warnings from gcc 4.7.0. The compiler
-    performs an optimization which is safe; however it then warns about it.
-    Changing the type of 'palette_number' in pngvalid.c removes the warning.
-  Do not depend upon a GCC feature macro being available for use in generating
-    the linker mapfile symbol prefix.
-  Improved performance of new do_check_palette_indexes() function (only
-    update the value when it actually increases, move test for whether
-    the check is wanted out of the function.
-
-Version 1.6.0beta24 [June 7, 2012]
-  Don't check palette indexes if num_palette is 0 (as it can be in MNG files).
-
-Version 1.6.0beta25 [June 16, 2012]
-  Revised png_set_keep_unknown_chunks() so num_chunks < 0 means ignore all
-    unknown chunks and all known chunks except for IHDR, PLTE, tRNS, IDAT,
-    and IEND.  Previously it only meant ignore all unknown chunks, the
-    same as num_chunks == 0. Revised png_image_skip_unused_chunks() to
-    provide a list of chunks to be processed instead of a list of chunks to
-    ignore.  Revised contrib/gregbook/readpng2.c accordingly.
-
-Version 1.6.0beta26 [July 10, 2012]
-  Removed scripts/makefile.cegcc from the *.zip and *.7z distributions; it
-    depends on configure, which is not included in those archives.
-  Moved scripts/chkfmt to contrib/tools.
-  Changed "a+w" to "u+w" in Makefile.in to fix CVE-2012-3386.
-
-Version 1.6.0beta27 [August 11, 2012]
-  Do not compile PNG_DEPRECATED, PNG_ALLOC and PNG_PRIVATE when __GNUC__ < 3.
-  Do not use __restrict when GNUC is <= 3.1
-  Removed references to png_zalloc() and png_zfree() from the manual.
-  Fixed configurations where floating point is completely disabled.  Because
-    of the changes to support symbol prefixing PNG_INTERNAL_FUNCTION declares
-    floating point APIs during libpng builds even if they are completely
-    disabled. This requires the png floating point types (png_double*) to be
-    declared even though the functions are never actually defined.  This
-    change provides a dummy definition so that the declarations work, yet any
-    implementation will fail to compile because of an incomplete type.
-  Re-eliminated the use of strcpy() in pngtest.c.  An unncessary use of
-    strcpy() was accidentally re-introduced in libpng16; this change replaces
-    it with strncpy().
-  Eliminated use of png_sizeof(); use sizeof() instead.
-  Use a consistent style for (sizeof type) and (sizeof (array))
-  Cleanup of png_set_filler().  This function does very different things on
-    read and write.  In libpng 1.6 the two cases can be distinguished and
-    considerable code cleanup, and extra error checking, is possible.  This
-    makes calls on the write side that have no effect be ignored with a
-    png_app_error(), which can be disabled in the app using
-    png_set_benign_errors(), and removes the spurious use of usr_channels
-    on the read side.
-  Insist on autotools 1.12.1 for git builds because there are security issues
-    with 1.12 and insisting on anything less would allow 1.12 to be used.
-  Removed info_ptr->signature[8] from WRITE-only builds.
-  Add some conditions for compiling png_fixed().  This is a small function
-    but it requires "-lm" on some platforms.
-  Cause pngtest --strict to fail on any warning from libpng (not just errors)
-    and cause it not to fail at the comparison step if libpng lacks support
-    for writing chunks that it reads from the input (currently only implemented
-    for compressed text chunks).
-  Make all three "make check" test programs work without READ or WRITE support.
-    Now "make check" will succeed even if libpng is compiled with -DPNG_NO_READ
-    or -DPNG_NO_WRITE.  The tests performed are reduced, but the basic reading
-    and writing of a PNG file is always tested by one or more of the tests.
-  Consistently use strlen(), memset(), memcpy(), and memcmp() instead of the
-    png_strlen(), png_memset(), png_memcpy(), and png_memcmp() macros.
-  Removed the png_sizeof(), png_strlen(), png_memset(), png_memcpy(), and
-    png_memcmp() macros.
-  Work around gcc 3.x and Microsoft Visual Studio 2010 complaints. Both object
-    to the split initialization of num_chunks.
-
-Version 1.6.0beta28 [August 29, 2012]
-  Unknown handling fixes and clean up. This adds more correct option
-    control of the unknown handling, corrects the pre-existing bug where
-    the per-chunk 'keep' setting is ignored and makes it possible to skip
-    IDAT chunks in the sequential reader (broken in earlier 1.6 versions).
-    There is a new test program, test-unknown.c, which is a work in progress
-    (not currently part of the test suite).  Comments in the header files now
-    explain how the unknown handling works.
-  Allow fine grain control of unknown chunk APIs. This change allows
-    png_set_keep_unknown_chunks() to be turned off if not required and causes
-    both read and write to behave appropriately (on read this is only possible
-    if the user callback is used to handle unknown chunks).  The change
-    also removes the support for storing unknown chunks in the info_struct
-    if the only unknown handling enabled is via the callback, allowing libpng
-    to be configured with callback reading and none of the unnecessary code.
-  Corrected fix for unknown handling in pngtest. This reinstates the
-    libpng handling of unknown chunks other than vpAg and sTER (including
-    unsafe-to-copy chunks which were dropped before) and eliminates the
-    repositioning of vpAg and sTER in pngtest.png by changing pngtest.png
-    (so the chunks are where libpng would put them).
-  Added "tunknown" test and corrected a logic error in png_handle_unknown()
-    when SAVE support is absent.  Moved the shell test scripts for
-    contrib/libtests from the libpng top directory to contrib/libtests.
-    png_handle_unknown() must always read or skip the chunk, if
-    SAVE_UNKNOWN_CHUNKS is turned off *and* the application does not set
-    a user callback an unknown chunk will not be read, leading to a read
-    error, which was revealed by the "tunknown" test.
-  Cleaned up and corrected ICC profile handling.
-    contrib/libtests/makepng: corrected 'rgb' and 'gray' cases.  profile_error
-    messages could be truncated; made a correct buffer size calculation and
-    adjusted pngerror.c appropriately. png_icc_check_* checking improved;
-    changed the functions to receive the correct color type of the PNG on read
-    or write and check that it matches the color space of the profile (despite
-    what the comments said before, there is danger in assuming the app will
-    cope correctly with an RGB profile on a grayscale image and, since it
-    violates the PNG spec, allowing it is certain to produce inconsistent
-    app behavior and might even cause app crashes.) Check that profiles
-    contain the tags needed to process the PNG (tags all required by the ICC
-    spec). Removed unused PNG_STATIC from pngpriv.h.
-
-Version 1.6.0beta29 [September 4, 2012]
-  Fixed the simplified API example programs to add the *colormap parameter
-    to several of he API and improved the error message if the version field
-    is not set.
-  Added contrib/examples/* to the *.zip and *.7z distributions.
-  Updated simplified API synopses and description of the png_image structure
-    in the manual.
-  Made makepng and pngtest produce identical PNGs, add "--relaxed" option
-    to pngtest. The "--relaxed" option turns off the benign errors that are
-    enabled by default in pre-RC builds. makepng can now write ICC profiles
-    where the length has not been extended to a multiple of 4, and pngtest
-    now intercepts all libpng errors, allowing the previously-introduced
-    "--strict test" on no warnings to actually work.
-  Improved ICC profile handling including cHRM chunk generation and fixed
-    Cygwin+MSVC build errors. The ICC profile handling now includes more
-    checking.  Several errors that caused rejection of the profile are now
-    handled with a warning in such a way that the invalid profiles will be
-    read by default in release (but not pre-RC) builds but will not be
-    written by default.  The easy part of handling the cHRM chunk is written,
-    where the ICC profile contains the required data.  The more difficult
-    part plus guessing a gAMA value requires code to pass selected RGB values
-    through the profile.
-
-Version 1.6.0beta30 [October 24, 2012]
-  Changed ICC profile matrix/vector types to not depend on array type rules.
-    By the ANSI-C standard the new types should be identical to the previous
-    versions, and all known versions of gcc tested with the previous versions
-    except for GCC-4.2.1 work with this version.  The change makes the ANSI-C
-    rule that const applied to an array of elements applies instead to the
-    elements in the array moot by explicitly applying const to the base
-    elements of the png_icc_matrix and png_icc_vector types. The accidental
-    (harmless) 'const' previously applied to the parameters of two of the
-    functions have also been removed.
-  Added a work around for GCC 4.2 optimization bug.
-  Marked the broken (bad white point) original HP sRGB profiles correctly and
-    correct comments.
-  Added -DZ_SOLO to contrib/pngminim/*/makefile to work with zlib-1.2.7
-  Use /MDd for vstudio debug builds. Also added pngunkown to the vstudio
-    builds, fixed build errors and corrected a minor exit code error in
-    pngvalid if the 'touch' file name is invalid.
-  Add updated WARNING file to projects/vstudio from libpng 1.5/vstudio
-  Fixed build when using #define PNG_NO_READ_GAMMA in png_do_compose() in
-    pngrtran.c (Domani Hannes).
-
-Version 1.6.0beta31 [November 1, 2012]
-  Undid the erroneous change to vstudio/pngvalid build in libpng-1.6.0beta30.
-  Made pngvalid so that it will build outside the libpng source tree.
-  Made builds -DPNG_NO_READ_GAMMA compile (the unit tests still fail).
-  Made PNG_NO_READ_GAMMA switch off interfaces that depend on READ_GAMMA.
-    Prior to 1.6.0 switching off READ_GAMMA did unpredictable things to the
-    interfaces that use it (specifically, png_do_background in 1.4 would
-    simply display composite for grayscale images but do composition
-    with the incorrect arithmetic for color ones). In 1.6 the semantic
-    of -DPNG_NO_READ_GAMMA is changed to simply disable any interface that
-    depends on it; this obliges people who set it to consider whether they
-    really want it off if they happen to use any of the interfaces in
-    question (typically most users who disable it won't).
-  Fixed GUIDs in projects/vstudio. Some were duplicated or missing,
-    resulting in VS2010 having to update the files.
-  Removed non-working ICC profile support code that was mostly added to
-    libpng-1.6.0beta29 and beta30. There was too much code for too little
-    gain; implementing full ICC color correction may be desireable but is left
-    up to applications.
-
-Version 1.6.0beta32 [November 25, 2012]
-  Fixed an intermittent SEGV in pngstest due to an uninitialized array element.
-  Added the ability for contrib/libtests/makepng.c to make a PNG with just one
-    color. This is useful for debugging pngstest color inaccuracy reports.
-  Fixed error checking in the simplified write API (Olaf van der Spek)
-  Made png_user_version_check() ok to use with libpng version 1.10.x and later.
-
-Version 1.6.0beta33 [December 15, 2012]
-  Fixed typo in png.c (PNG_SET_CHUNK_MALLOC_MAX should be PNG_CHUNK_MALLOC_MAX)
-    that causes the MALLOC_MAX limit not to work (John Bowler)
-  Change png_warning() to png_app_error() in pngwrite.c and comment the
-    fall-through condition.
-  Change png_warning() to png_app_warning() in png_write_tRNS().
-  Rearranged the ARM-NEON optimizations: Isolated the machine specific code
-    to the hardware subdirectory and added comments to pngrutil.c so that
-    implementors of other optimizations know what to do.
-  Fixed cases of unquoted DESTDIR in Makefile.am
-  Rebuilt Makefile.in, etc., with autoconf-2.69 and automake-1.12.5.
-
-Version 1.6.0beta34 [December 19, 2012]
-  Cleaned up whitespace in the synopsis portion of the manpage "libpng.3"
-  Disassembled the version number in scripts/options.awk (necessary for
-    building on SunOs).
-
-Version 1.6.0beta35 [December 23, 2012]
-  Made default Zlib compression settings be configurable. This adds #defines to
-    pnglibconf.h to control the defaults.
-  Fixed Windows build issues, enabled ARM compilation. Various warnings issued
-    by earlier versions of GCC fixed for Cygwin and Min/GW (which both use old
-    GCCs.) ARM support is enabled by default in zlib.props (unsupported by
-    Microsoft) and ARM compilation is made possible by deleting the check for
-    x86. The test programs cannot be run because they are not signed.
-
-Version 1.6.0beta36 [January 2, 2013]
-  Discontinued distributing libpng-1.x.x.tar.bz2.
-  Discontinued distributing libpng-1.7.0-1.6.0-diff.txt and similar.
-  Rebuilt configure with autoconf-2.69 (inadvertently not done in beta33)
-  Fixed 'make distcheck' on SUN OS - libpng.so was not being removed
-
-Version 1.6.0beta37 [January 10, 2013]
-  Fixed conceivable but difficult to repro overflow. Also added two test
-    programs to generate and test a PNG which should have the problem.
-
-Version 1.6.0beta39 [January 19, 2013]
-  Again corrected attempt at overflow detection in png_set_unknown_chunks()
-  (CVE-2013-7353).  Added overflow detection in png_set_sPLT() and
-  png_set_text_2() (CVE-2013-7354).
-
-Version 1.6.0beta40 [January 20, 2013]
-  Use consistent handling of overflows in text, sPLT and unknown png_set_* APIs
-
-Version 1.6.0rc01 [January 26, 2013]
-  No changes.
-
-Version 1.6.0rc02 [February 4, 2013]
-  Added png_get_palette_max() function.
-
-Version 1.6.0rc03 [February 5, 2013]
-  Fixed the png_get_palette_max API.
-
-Version 1.6.0rc04 [February 7, 2013]
-  Turn serial tests back on (recently turned off by autotools upgrade).
-
-Version 1.6.0rc05 [February 8, 2013]
-  Update manual about png_get_palette_max().
-
-Version 1.6.0rc06 [February 9, 2013]
-  Fixed missing dependency in --prefix builds The intermediate
-    internal 'prefix.h' file can only be generated correctly after
-    pnglibconf.h, however the dependency was not in Makefile.am.  The
-    symptoms are unpredictable depending on the order make chooses to
-    build pngprefix.h and pnglibconf.h, often the error goes unnoticed
-    because there is a system pnglibconf.h to use instead.
-
-Version 1.6.0rc07 [February 10, 2013]
-  Enclosed the new png_get_palette_max in #ifdef PNG_GET_PALETTE_MAX_SUPPORTED
-    block, and revised pnglibconf.h and pnglibconf.h.prebuilt accordingly.
-
-Version 1.6.0rc08 [February 10, 2013]
-  Fix typo in png.h #ifdef
-
-Version 1.6.0 [February 14, 2013]
-  No changes.
-
-Version 1.6.1beta01 [February 16, 2013]
-  Made symbol prefixing work with the ARM neon optimizations. Also allow
-    pngpriv.h to be included for preprocessor definitions only, so it can
-    be used in non-C/C++ files. Back ported from libpng 1.7.
-  Made sRGB check numbers consistent.
-  Ported libpng 1.5 options.awk/dfn file handling to 1.6, fixed one bug.
-  Removed cc -E workround, corrected png_get_palette_max API Tested on
-    SUN OS cc 5.9, which demonstrates the tokenization problem previously
-    avoided by using /lib/cpp.  Since all .dfn output is now protected in
-    double quotes unless it is to be macro substituted the fix should
-    work everywhere.
-  Enabled parallel tests - back ported from libpng-1.7.
-  scripts/pnglibconf.dfa formatting improvements back ported from libpng17.
-  Fixed a race condition in the creation of the build 'scripts' directory
-    while building with a parallel make.
-  Use approved/supported Android method to check for NEON, use Linux/POSIX
-    1003.1 API to check /proc/self/auxv avoiding buffer allocation and other
-    library calls (ported from libpng15).
-
-Version 1.6.1beta02 [February 19, 2013]
-  Use parentheses more consistently in "#if defined(MACRO)" tests.
-  Folded long lines.
-  Reenabled code to allow zero length PLTE chunks for MNG.
-
-Version 1.6.1beta03 [February 22, 2013]
-  Fixed ALIGNED_MEMORY support.
-  Added a new configure option:
-    --enable-arm-neon=always will stop the run-time checks. New checks
-    within arm/arm_init.c will cause the code not to be compiled unless
-    __ARM_NEON__ is set. This should make it fail safe (if someone asks
-    for it on then the build will fail if it can't be done.)
-  Updated the INSTALL document.
-
-Version 1.6.1beta04 [February 27, 2013]
-  Revised INSTALL to recommend using CPPFLAGS instead of INCLUDES.
-  Revised scripts/makefile.freebsd to respect ZLIBLIB and ZLIBINC.
-  Revised scripts/dfn.awk to work with the buggy MSYS awk that has trouble
-    with CRLF line endings.
-
-Version 1.6.1beta05 [March 1, 2013]
-  Avoid a possible memory leak in contrib/gregbook/readpng.c
-
-Version 1.6.1beta06 [March 4, 2013]
-  Better documentation of unknown handling API interactions.
-  Corrected Android builds and corrected libpng.vers with symbol
-    prefixing.  It also makes those tests compile and link on Android.
-  Added an API png_set_option() to set optimization options externally,
-    providing an alternative and general solution for the non-portable
-    run-time tests used by the ARM Neon code, using the PNG_ARM_NEON option.
-  The order of settings vs options in pnglibconf.h is reversed to allow
-    settings to depend on options and options can now set (or override) the
-    defaults for settings.
-
-Version 1.6.1beta07 [March 7, 2013]
-  Corrected simplified API default gamma for color-mapped output, added
-    a flag to change default. In 1.6.0 when the simplified API was used
-    to produce color-mapped output from an input image with no gamma
-    information the gamma assumed for the input could be different from
-    that assumed for non-color-mapped output.  In particular 16-bit depth
-    input files were assumed to be sRGB encoded, whereas in the 'direct'
-    case they were assumed to have linear data.  This was an error.  The
-    fix makes the simplified API treat all input files the same way and
-    adds a new flag to the png_image::flags member to allow the
-    application/user to specify that 16-bit files contain sRGB data
-    rather than the default linear.
-  Fixed bugs in the pngpixel and makepng test programs.
-
-Version 1.6.1beta08 [March 7, 2013]
-  Fixed CMakelists.txt to allow building a single variant of the library
-    (Claudio Bley):
-  Introduced a PNG_LIB_TARGETS variable that lists all activated library
-    targets.  It is an error if this variable ends up empty, ie. you have
-    to build at least one library variant.
-  Made the *_COPY targets only depend on library targets actually being build.
-  Use PNG_LIB_TARGETS to unify a code path.
-  Changed the CREATE_SYMLINK macro to expect the full path to a file as the
-    first argument. When symlinking the filename component of that path is
-    determined and used as the link target.
-  Use copy_if_different in the CREATE_SYMLINK macro.
-
-Version 1.6.1beta09 [March 13, 2013]
-  Eliminated two warnings from the Intel C compiler. The warnings are
-    technically valid, although a reasonable treatment of division would
-    show it to be incorrect.
-
-Version 1.6.1rc01 [March 21, 2013]
-  No changes.
-
-Version 1.6.1 [March 28, 2013]
-  No changes.
-
-Version 1.6.2beta01 [April 14, 2013]
-  Updated documentation of 1.5.x to 1.6.x changes in iCCP chunk handling.
-  Fixed incorrect warning of excess deflate data. End condition - the
-    warning would be produced if the end of the deflate stream wasn't read
-    in the last row.  The warning is harmless.
-  Corrected the test on user transform changes on read. It was in the
-    png_set of the transform function, but that doesn't matter unless the
-    transform function changes the rowbuf size, and that is only valid if
-    transform_info is called.
-  Corrected a misplaced closing bracket in contrib/libtests/pngvalid.c
-    (Flavio Medeiros).
-  Corrected length written to uncompressed iTXt chunks (Samuli Suominen).
-    Bug was introduced in libpng-1.6.0.
-
-Version 1.6.2rc01 [April 18, 2013]
-  Added contrib/tools/fixitxt.c, to repair the erroneous iTXt chunk length
-    written by libpng-1.6.0 and 1.6.1.
-  Disallow storing sRGB information when the sRGB is not supported.
-
-Version 1.6.2rc02 [April 18, 2013]
-  Merge pngtest.c with libpng-1.7.0
-
-Version 1.6.2rc03 [April 22, 2013]
-  Trivial spelling cleanup.
-
-Version 1.6.2rc04 and 1.6.2rc05 [omitted]
-
-Version 1.6.2rc06 [April 24, 2013]
-  Reverted to version 1.6.2rc03.  Recent changes to arm/neon support
-    have been ported to libpng-1.7.0beta09 and will reappear in version
-    1.6.3beta01.
-
-Version 1.6.2 [April 25, 2013]
-  No changes.
-
-Version 1.6.3beta01 [April 25, 2013]
-  Revised stack marking in arm/filter_neon.S and configure.ac.
-  Ensure that NEON filter stuff is completely disabled when switched 'off'.
-    Previously the ARM NEON specific files were still built if the option
-    was switched 'off' as opposed to being explicitly disabled.
-
-Version 1.6.3beta02 [April 26, 2013]
-  Test for 'arm*' not just 'arm' in the host_cpu configure variable.
-  Rebuilt the configure scripts.
-
-Version 1.6.3beta03 [April 30, 2013]
-  Expanded manual paragraph about writing private chunks, particularly
-    the need to call png_set_keep_unknown_chunks() when writing them.
-  Avoid dereferencing NULL pointer possibly returned from
-    png_create_write_struct() (Andrew Church).
-
-Version 1.6.3beta05 [May 9, 2013]
-  Calculate our own zlib windowBits when decoding rather than trusting the
-    CMF bytes in the PNG datastream.
-  Added an option to force maximum window size for inflating, which was
-    the behavior of libpng15 and earlier, via a new PNG_MAXIMUM_INFLATE_WINDOW
-    option for png_set_options().
-  Added png-fix-itxt and png-fix-too-far-back to the built programs and
-    removed warnings from the source code and timepng that are revealed as
-    a result.
-  Detect wrong libpng versions linked to png-fix-too-far-back, which currently
-    only works with libpng versions that can be made to reliably fail when
-    the deflate data contains an out-of-window reference.  This means only
-    1.6 and later.
-  Fixed gnu issues: g++ needs a static_cast, gcc 4.4.7 has a broken warning
-    message which it is easier to work round than ignore.
-  Updated contrib/pngminus/pnm2png.c (Paul Stewart):
-    Check for EOF
-    Ignore "#" delimited comments in input file to pnm2png.c.
-    Fixed whitespace handling
-    Added a call to png_set_packing()
-    Initialize dimension values so if sscanf fails at least we have known
-      invalid values.
-  Attempt to detect configuration issues with png-fix-too-far-back, which
-    requires both the correct libpng and the correct zlib to function
-    correctly.
-  Check ZLIB_VERNUM for mismatches, enclose #error in quotes
-  Added information in the documentation about problems with and fixes for
-    the bad CRC and bad iTXt chunk situations.
-
-Version 1.6.3beta06 [May 12, 2013]
-  Allow contrib/pngminus/pnm2png.c to compile without WRITE_INVERT and
-    WRITE_PACK supported (writes error message that it can't read P1 or
-    P4 PBM files).
-  Improved png-fix-too-far-back usage message, added --suffix option.
-  Revised contrib/pngminim/*/makefile to generate pnglibconf.h with the
-    right zlib header files.
-  Separated CPPFLAGS and CFLAGS in contrib/pngminim/*/makefile
-
-Version 1.6.3beta07 [June 8, 2013]
-  Removed a redundant test in png_set_IHDR().
-  Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
-  Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
-  Enclose the prototypes for the simplified write API in
-    #ifdef PNG_STDIO_SUPPORTED/#endif
-  Make ARM NEON support work at compile time (not just configure time).
-    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
-    using a compiler that compiles for multiple architectures at one time.
-  Removed PNG_FILTER_OPTIMIZATIONS and PNG_ARM_NEON_SUPPORTED from
-    pnglibconf.h, allowing more of the decisions to be made internally
-    (pngpriv.h) during the compile.  Without this, symbol prefixing is broken
-    under certain circumstances on ARM platforms.  Now only the API parts of
-    the optimizations ('check' vs 'api') are exposed in the public header files
-    except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the
-    decision about whether or not to use the optimizations.
-  Protect symbol prefixing against CC/CPPFLAGS/CFLAGS useage.
-    Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test
-    on __ARM_NEON__ from configure time to compile time.  This breaks symbol
-    prefixing because the definition of the special png_init_filter_functions
-    call was hidden at configure time if the relevant compiler arguments are
-    passed in CFLAGS as opposed to CC.  This change attempts to avoid all
-    the confusion that would result by declaring the init function even when
-    it is not used, so that it will always get prefixed.
-
-Version 1.6.3beta08 [June 18, 2013]
-  Revised libpng.3 so that "doclifter" can process it.
-
-Version 1.6.3beta09 [June 27, 2013]
-  Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
-    as parameters for png_set_gamma().  These have been available since
-    libpng-1.5.4.
-  Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
-    to check all compressed chunks known to libpng.
-
-Version 1.6.3beta10 [July 5, 2013]
-  Updated documentation to show default behavior of benign errors correctly.
-  Only compile ARM code when PNG_READ_SUPPORTED is defined.
-  Fixed undefined behavior in contrib/tools/pngfix.c and added new strip
-    option. pngfix relied on undefined behavior and even a simple change from
-    gcc to g++ caused it to fail.  The new strip option 'unsafe' has been
-    implemented and is the default if --max is given.  Option names have
-    been clarified, with --strip=transform now stripping the bKGD chunk,
-    which was stripped previously with --strip=unused.
-  Added all documented chunk types to pngpriv.h
-  Unified pngfix.c source with libpng17.
-
-Version 1.6.3rc01 [July 11, 2013]
-  No changes.
-
-Version 1.6.3 [July 18, 2013]
-  Revised manual about changes in iTXt chunk handling made in libpng-1.6.0.
-  Added "/* SAFE */" comments in pngrutil.c and pngrtran.c where warnings
-    may be erroneously issued by code-checking applications.
-
-Version 1.6.4beta01 [August 21, 2013]
-  Added information about png_set_options() to the manual.
-  Delay calling png_init_filter_functions() until a row with nonzero filter
-    is found.
-
-Version 1.6.4beta02 [August 30, 2013]
-  Fixed inconsistent conditional compilation of png_chunk_unknown_handling()
-    prototype, definition, and usage.  Made it depend on
-    PNG_HANDLE_AS_UNKNOWN_SUPPORTED everywhere.
-
-Version 1.6.4rc01 [September 5, 2013]
-  No changes.
-
-Version 1.6.4 [September 12, 2013]
-  No changes.
-
-Version 1.6.5 [September 14, 2013]
-  Removed two stray lines of code from arm/arm_init.c.
-
-Version 1.6.6 [September 16, 2013]
-  Removed two stray lines of code from arm/arm_init.c, again.
-
-Version 1.6.7beta01 [September 30, 2013]
-  Revised unknown chunk code to correct several bugs in the NO_SAVE_/NO_WRITE
-    combination
-  Allow HANDLE_AS_UNKNOWN to work when other options are configured off. Also
-    fixed the pngminim makefiles to work when $(MAKEFLAGS) contains stuff
-    which terminates the make options (as by default in recent versions of
-    Gentoo).
-  Avoid up-cast warnings in pngvalid.c. On ARM the alignment requirements of
-    png_modifier are greater than that of png_store and as a consequence
-    compilation of pngvalid.c results in a warning about increased alignment
-    requirements because of the bare cast to (png_modifier*). The code is safe,
-    because the pointer is known to point to a stack allocated png_modifier,
-    but this change avoids the warning.
-  Fixed default behavior of ARM_NEON_API. If the ARM NEON API option was
-    compiled without the CHECK option it defaulted to on, not off.
-  Check user callback behavior in pngunknown.c. Previous versions compiled
-    if SAVE_UNKNOWN was not available but did nothing since the callback
-    was never implemented.
-  Merged pngunknown.c with 1.7 version and back ported 1.7 improvements/fixes
-
-Version 1.6.7beta02 [October 12, 2013]
-  Made changes for compatibility with automake 1.14:
-    1) Added the 'compile' program to the list of programs that must be cleaned
-       in autogen.sh
-    2) Added 'subdir-objects' which causes .c files in sub-directories to be
-       compiled such that the corresponding .o files are also in the
-       sub-directory.  This is because automake 1.14 warns that the
-       current behavior of compiling to the top level directory may be removed
-       in the future.
-    3) Updated dependencies on pnglibconf.h to match the new .o locations and
-       added all the files in contrib/libtests and contrib/tools that depend
-       on pnglibconf.h
-    4) Added 'BUILD_SOURCES = pnglibconf.h'; this is the automake recommended
-       way of handling the dependencies of sources that are machine generated;
-       unfortunately it only works if the user does 'make all' or 'make check',
-       so the dependencies (3) are still required.
-  Cleaned up (char*) casts of zlib messages. The latest version of the Intel C
-    compiler complains about casting a string literal as (char*), so copied the
-    treatment of z_const from the library code into pngfix.c
-  Simplified error message code in pngunknown. The simplification has the
-    useful side effect of avoiding a bogus warning generated by the latest
-    version of the Intel C compiler (it objects to
-    condition ? string-literal : string-literal).
-  Make autogen.sh work with automake 1.13 as well as 1.14. Do this by always
-    removing the 1.14 'compile' script but never checking for it.
-
-Version 1.6.7beta03 [October 19, 2013]
-  Added ARMv8 support (James Yu <james.yu at linaro.org>).  Added file
-    arm/filter_neon_intrinsics.c; enable with -mfpu=neon.
-  Revised pngvalid to generate size images with as many filters as it can
-    manage, limited by the number of rows.
-  Cleaned up ARM NEON compilation handling. The tests are now in pngpriv.h
-    and detect the broken GCC compilers.
-
-Version 1.6.7beta04 [October 26, 2013]
-  Allow clang derived from older GCC versions to use ARM intrinsics. This
-    causes all clang builds that use -mfpu=neon to use the intrinsics code,
-    not the assembler code.  This has only been tested on iOS 7. It may be
-    necessary to exclude some earlier clang versions but this seems unlikely.
-  Changed NEON implementation selection mechanism. This allows assembler
-    or intrinsics to be turned on at compile time during the build by defining
-    PNG_ARM_NEON_IMPLEMENTATION to the correct value (2 or 1).  This macro
-    is undefined by default and the build type is selected in pngpriv.h.
-
-Version 1.6.7rc01 [November 2, 2013]
-  No changes.
-
-Version 1.6.7rc02 [November 7, 2013]
-  Fixed #include in filter_neon_intrinsics.c and ctype macros. The ctype char
-    checking macros take an unsigned char argument, not a signed char.
-
-Version 1.6.7 [November 14, 2013]
-  No changes.
-
-Version 1.6.8beta01 [November 24, 2013]
-  Moved prototype for png_handle_unknown() in pngpriv.h outside of
-    the #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED/#endif block.
-  Added "-Wall" to CFLAGS in contrib/pngminim/*/makefile
-  Conditionally compile some unused functions reported by -Wall in
-    pngminim.
-  Fixed 'minimal' builds. Various obviously useful minimal configurations
-    don't build because of missing contrib/libtests test programs and
-    overly complex dependencies in scripts/pnglibconf.dfa. This change
-    adds contrib/conftest/*.dfa files that can be used in automatic build
-    scripts to ensure that these configurations continue to build.
-  Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
-  Fixed pngvalid 'fail' function declaration on the Intel C Compiler.
-    This reverts to the previous 'static' implementation and works round
-    the 'unused static function' warning by using PNG_UNUSED().
-
-Version 1.6.8beta02 [November 30, 2013]
-  Removed or marked PNG_UNUSED some harmless "dead assignments" reported
-    by clang scan-build.
-  Changed tabs to 3 spaces in png_debug macros and changed '"%s"m'
-    to '"%s" m' to improve portability among compilers.
-  Changed png_free_default() to free() in pngtest.c
-
-Version 1.6.8rc01 [December 12, 2013]
-  Tidied up pngfix inits and fixed pngtest no-write builds.
-
-Version 1.6.8rc02 [December 14, 2013]
-  Handle zero-length PLTE chunk or NULL palette with png_error()
-    instead of png_chunk_report(), which by default issues a warning
-    rather than an error, leading to later reading from a NULL pointer
-    (png_ptr->palette) in png_do_expand_palette(). This is CVE-2013-6954
-    and VU#650142.  Libpng-1.6.1 through 1.6.7 are vulnerable.
-    Libpng-1.6.0 and earlier do not have this bug.
-
-Version 1.6.8 [December 19, 2013]
-  No changes.
-
-Version 1.6.9beta01 [December 26, 2013]
-  Bookkeeping: Moved functions around (no changes). Moved transform
-    function definitions before the place where they are called so that
-    they can be made static. Move the intrapixel functions and the
-    grayscale palette builder out of the png?tran.c files. The latter
-    isn't a transform function and is no longer used internally, and the
-    former MNG specific functions are better placed in pngread/pngwrite.c
-  Made transform implementation functions static. This makes the internal
-    functions called by png_do_{read|write}_transformations static. On an
-    x86-64 DLL build (Gentoo Linux) this reduces the size of the text
-    segment of the DLL by 1208 bytes, about 0.6%. It also simplifies
-    maintenance by removing the declarations from pngpriv.h and allowing
-    easier changes to the internal interfaces.
-  Rebuilt configure scripts with automake-1.14.1 and autoconf-2.69
-    in the tar distributions.
-
-Version 1.6.9beta02 [January 1, 2014]
-  Added checks for libpng 1.5 to pngvalid.c.  This supports the use of
-    this version of pngvalid in libpng 1.5
-  Merged with pngvalid.c from libpng-1.7 changes to create a single
-    pngvalid.c
-  Removed #error macro from contrib/tools/pngfix.c (Thomas Klausner).
-  Merged pngrio.c, pngtrans.c, pngwio.c, and pngerror.c with libpng-1.7.0
-  Merged libpng-1.7.0 changes to make no-interlace configurations work
-    with test programs.
-  Revised pngvalid.c to support libpng 1.5, which does not support the
-    PNG_MAXIMUM_INFLATE_WINDOW option, so #define it out when appropriate in
-    pngvalid.c
-  Allow unversioned links created on install to be disabled in configure.
-    In configure builds 'make install' changes/adds links like png.h
-    and libpng.a to point to the newly installed, versioned, files (e.g.
-    libpng17/png.h and libpng17.a). Three new configure options and some
-    rearrangement of Makefile.am allow creation of these links to be disabled.
-
-Version 1.6.9beta03 [January 10, 2014]
-  Removed potentially misleading warning from png_check_IHDR().
-
-Version 1.6.9beta04 [January 20, 2014]
-  Updated scripts/makefile.* to use CPPFLAGS (Cosmin).
-  Added clang attribute support (Cosmin).
-
-Version 1.6.9rc01 [January 28, 2014]
-  No changes.
-
-Version 1.6.9rc02 [January 30, 2014]
-  Quiet an uninitialized memory warning from VC2013 in png_get_png().
-
-Version 1.6.9 [February 6, 2014]
-
-Version 1.6.10beta01 [February 9, 2014]
-  Backported changes from libpng-1.7.0beta30 and beta31:
-  Fixed a large number of instances where PNGCBAPI was omitted from
-    function definitions.
-  Added pngimage test program for png_read_png() and png_write_png()
-    with two new test scripts.
-  Removed dependence on !PNG_READ_EXPAND_SUPPORTED for calling
-    png_set_packing() in png_read_png().
-  Fixed combination of ~alpha with shift. On read invert alpha, processing
-    occurred after shift processing, which causes the final values to be
-    outside the range that should be produced by the shift. Reversing the
-    order on read makes the two transforms work together correctly and mirrors
-    the order used on write.
-  Do not read invalid sBIT chunks. Previously libpng only checked sBIT
-    values on write, so a malicious PNG writer could therefore cause
-    the read code to return an invalid sBIT chunk, which might lead to
-    application errors or crashes.  Such chunks are now skipped (with
-    chunk_benign_error).
-  Make png_read_png() and png_write_png() prototypes in png.h depend
-    upon PNG_READ_SUPPORTED and PNG_WRITE_SUPPORTED.
-  Support builds with unsupported PNG_TRANSFORM_* values.  All of the
-    PNG_TRANSFORM_* values are always defined in png.h and, because they
-    are used for both read and write in some cases, it is not reliable
-    to #if out ones that are totally unsupported. This change adds error
-    detection in png_read_image() and png_write_image() to do a
-    png_app_error() if the app requests something that cannot be done
-    and it adds corresponding code to pngimage.c to handle such options
-    by not attempting to test them.
-
-Version 1.6.10beta02 [February 23, 2014]
-  Moved redefines of png_error(), png_warning(), png_chunk_error(),
-    and png_chunk_warning() from pngpriv.h to png.h to make them visible
-    to libpng-calling applications.
-  Moved OS dependent code from arm/arm_init.c, to allow the included
-    implementation of the ARM NEON discovery function to be set at
-    build-time and provide sample implementations from the current code in the
-    contrib/arm-neon subdirectory. The __linux__ code has also been changed to
-    compile and link on Android by using /proc/cpuinfo, and the old linux code
-    is in contrib/arm-neon/linux-auxv.c.  The new code avoids POSIX and Linux
-    dependencies apart from opening /proc/cpuinfo and is C90 compliant.
-  Check for info_ptr == NULL early in png_read_end() so we don't need to
-    run all the png_handle_*() and depend on them to return if info_ptr == NULL.
-    This improves the performance of png_read_end(png_ptr, NULL) and makes
-    it more robust against future programming errors.
-  Check for __has_extension before using it in pngconf.h, to
-    support older Clang versions (Jeremy Sequoia).
-  Treat CRC error handling with png_set_crc_action(), instead of with
-    png_set_benign_errors(), which has been the case since libpng-1.6.0beta18.
-  Use a user warning handler in contrib/gregbook/readpng2.c instead of default,
-    so warnings will be put on stderr even if libpng has CONSOLE_IO disabled.
-  Added png_ptr->process_mode = PNG_READ_IDAT_MODE in png_push_read_chunk
-    after recognizing the IDAT chunk, which avoids an infinite loop while
-    reading a datastream whose first IDAT chunk is of zero-length.
-    This fixes CERT VU#684412 and CVE-2014-0333.
-  Don't recognize known sRGB profiles as sRGB if they have been hacked,
-    but don't reject them and don't issue a copyright violation warning.
-
-Version 1.6.10beta03 [February 25, 2014]
-  Moved some documentation from png.h to libpng.3 and libpng-manual.txt
-  Minor editing of contrib/arm-neon/README and contrib/examples/*.c
-
-Version 1.6.10rc01 [February 27, 2014]
-  Fixed typos in the manual and in scripts/pnglibconf.dfa (CFLAGS -> CPPFLAGS
-    and PNG_USR_CONFIG -> PNG_USER_CONFIG).
-
-Version 1.6.10rc02 [February 28, 2014]
-  Removed unreachable return statement after png_chunk_error()
-    in pngrutil.c
-
-Version 1.6.10rc03 [March 4, 2014]
-  Un-deprecated png_data_freer().
-
-Version 1.6.10 [March 6, 2014]
-  No changes.
-
-Version 1.6.11beta01 [March 17, 2014]
-  Use "if (value != 0)" instead of "if (value)" consistently.
-  Changed ZlibSrcDir from 1.2.5 to 1.2.8 in projects/vstudio.
-  Moved configuration information from the manual to the INSTALL file.
-
-Version 1.6.11beta02 [April 6, 2014]
-  Removed #if/#else/#endif from inside two pow() calls in pngvalid.c because
-    they were handled improperly by Portland Group's PGI-14.1 - PGI-14.3
-    when using its "__builtin_pow()" function.
-  Silence 'unused parameter' build warnings (Cosmin Truta).
-  $(CP) is now used alongside $(RM_F).  Also, use 'copy' instead of 'cp'
-    where applicable, and applied other minor makefile changes (Cosmin).
-  Don't warn about invalid dimensions exceeding user limits (Cosmin).
-  Allow an easy replacement of the default pre-built configuration
-    header with a custom header, via the make PNGLIBCONF_H_PREBUILT
-    macro (Cosmin).
-
-Version 1.6.11beta03 [April 6, 2014]
-  Fixed a typo in pngrutil.c, introduced in libpng-1.5.6, that interferes
-    with "blocky" expansion of sub-8-bit interlaced PNG files (Eric Huss).
-  Optionally use  __builtin_bswap16() in png_do_swap().
-
-Version 1.6.11beta04 [April 19, 2014]
-  Made progressive reading of interlaced images consistent with the
-    behavior of the sequential reader and consistent with the manual, by
-    moving some code out of the PNG_READ_INTERLACING_SUPPORTED blocks. The
-    row_callback now receives the proper pass number and unexpanded rows, when
-    png_combine_row() isn't built or used, and png_set_interlace_handling()
-    is not called.
-  Allow PNG_sRGB_PROFILE_CHECKING = (-1) to mean no sRGB profile checking.
-
-Version 1.6.11beta05 [April 26, 2014]
-  Do not reject ICC V2 profiles that lack padding (Kai-Uwe Behrmann).
-  Relocated closing bracket of the sRGB profile test loop to avoid getting
-    "Not recognizing known sRGB profile that has been edited" warning for
-    ICC V2 profiles that lack the MD5 signature in the profile header.
-
-Version 1.6.11beta06 [May 19, 2014]
-  Added PNG_SKIP_sRGB_CHECK_PROFILE choice for png_set_option().
-
-Version 1.6.11rc01 [May 27, 2014]
-  No changes.
-
-Version 1.6.11rc02 [June 3, 2014]
-  Test ZLIB_VERNUM instead of PNG_ZLIB_VERNUM in contrib/tools/pngfix.c
-
-Version 1.6.11 [June 5, 2014]
-  No changes.
-
-Version 1.6.12rc01 [June 6, 2014]
-  Relocated new code from 1.6.11beta06 in png.c to a point after the
-    declarations (Max Stepin).
-
-Version 1.6.12rc02 [June 7, 2014]
-  Changed file permissions of contrib/tools/intgamma.sh,
-    test-driver, and compile from 0644 to 0755 (Cosmin).
-
-Version 1.6.12rc03 [June 8, 2014]
-  Ensure "__has_attribute()" macro exists before trying to use it with
-    old clang compilers (MacPorts Ticket #43939).
-
-Version 1.6.12 [June 12, 2014]
-  No changes.
-
-Version 1.6.13beta01 [July 4, 2014]
-  Quieted -Wsign-compare and -Wclobber compiler warnings in
-    contrib/pngminus/*.c
-  Added "(void) png_ptr;" where needed in contrib/gregbook to quiet
-    compiler complaints about unused pointers.
-  Split a long output string in contrib/gregbook/rpng2-x.c.
-  Added "PNG_SET_OPTION" requirement for sRGB chunk support to pnglibconf.dfa,
-    Needed for write-only support (John Bowler).
-  Changed "if defined(__ARM_NEON__)" to
-    "if (defined(__ARM_NEON__) || defined(__ARM_NEON))" (James Wu).
-  Fixed clang no-warning builds: png_digit was defined but never used.
-    
-Version 1.6.13beta02 [July 21, 2014]
-  Fixed an incorrect separator ("/" should be "\") in scripts/makefile.vcwin32
-    (bug report from Wolfgang S. Kechel).  Bug was introduced in libpng-1.6.11.
-    Also fixed makefile.bc32, makefile.bor, makefile.msc, makefile.intel, and
-    makefile.tc3 similarly.
-
-Version 1.6.13beta03 [August 3, 2014]
-  Removed scripts/makefile.elf. It has not worked since libpng-1.5.0beta14
-    due to elimination of the PNG_FUNCTION_EXPORT and PNG_DATA_EXPORT
-    definitions from pngconf.h.
-  Ensure that CMakeLists.txt makes the target "lib" directory before making
-    symbolic link into it (SourceForge bug report #226 by Rolf Timmermans).
-
-Version 1.6.13beta04 [August 8, 2014]
-  Added opinion that the ECCN (Export Control Classification Number) for
-    libpng is EAR99 to the README file.
-  Eliminated use of "$<" in makefile explicit rules, when copying
-    $PNGLIBCONF_H_PREBUILT.  This does not work on some versions of make;
-    bug introduced in libpng version 1.6.11.
-
-Version 1.6.13rc01 [August 14, 2014]
-  Made "ccopts" agree with "CFLAGS" in scripts/makefile.hp* and makefile.*sunu
-
-Version 1.6.13 [August 21, 2014]
-  No changes.
-
-Version 1.6.14beta01 [September 14, 2014]
-  Guard usage of png_ptr->options with #ifdef PNG_SET_OPTION_SUPPORTED.
-  Do not build contrib/tools/pngfix.c when PNG_SETJMP_NOT_SUPPORTED,
-    to allow "make" to complete without setjmp support (bug report by
-    Claudio Fontana)
-  Add "#include <setjmp.h>" to contrib/tools/pngfix.c (John Bowler)
-
-Version 1.6.14beta02 [September 18, 2014]
-  Use nanosleep() instead of usleep() in contrib/gregbook/rpng2-x.c
-    because usleep() is deprecated.
-  Define usleep() in contrib/gregbook/rpng2-x.c if not already defined
-    in unistd.h and nanosleep() is not available; fixes error introduced
-    in libpng-1.6.13.
-  Disable floating point exception handling in pngvalid.c when
-    PNG_FLOATING_ARITHMETIC is not supported (bug report by "zootus
-    at users.sourceforge.net").
-
-Version 1.6.14beta03 [September 19, 2014]
-  Define FE_DIVBYZERO, FE_INVALID, and FE_OVERFLOW in pngvalid.c if not
-    already defined.  Revert floating point exception handling in pngvalid.c
-    to version 1.6.14beta01 behavior.
-
-Version 1.6.14beta04 [September 27, 2014]
-  Fixed incorrect handling of the iTXt compression flag in pngrutil.c
-    (bug report by Shunsaku Hirata).  Bug was introduced in libpng-1.6.0.
-
-Version 1.6.14beta05 [October 1, 2014]
-  Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
-
-Version 1.6.14beta06 [October 5, 2014]
-  Removed unused "text_len" parameter from private function png_write_zTXt().
-  Conditionally compile some code in png_deflate_claim(), when
-    PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
-  Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
-  Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
-    to pnglibconf.dfa.
-  Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
-    to make it possible to configure a libpng that supports iCCP but not TEXT.
-
-Version 1.6.14beta07 [October 7, 2014]
-  Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
-  Only mark text chunks as written after successfully writing them.
-
-Version 1.6.14rc01 [October 15, 2014]
-  Fixed some typos in comments.
-
-Version 1.6.14rc02 [October 17, 2014]
-  Changed png_convert_to_rfc_1123() to png_convert_to_rfc_1123_buffer()
-    in the manual, to reflect the change made in libpng-1.6.0.
-  Updated README file to explain that direct access to the png_struct
-    and info_struct members has not been permitted since libpng-1.5.0.
-
-Version 1.6.14 [October 23, 2014]
-  No changes.
-
-Version 1.6.15beta01 [October 29, 2014]
-  Changed "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
-  Simplified png_free_data().
-  Added missing "ptr = NULL" after some instances of png_free().
-
-Version 1.6.15beta02 [November 1, 2014]
-  Changed remaining "if (!x)" to "if (x == 0)" and "if (x)" to "if (x != 0)"
-
-Version 1.6.15beta03 [November 3, 2014]
-  Added PNG_USE_ARM_NEON configuration flag (Marcin Juszkiewicz).
-
-Version 1.6.15beta04 [November 4, 2014]
-  Removed new PNG_USE_ARM_NEON configuration flag and made a one-line
-    revision to configure.ac to support ARM on aarch64 instead (John Bowler).
-
-Version 1.6.15beta05 [November 5, 2014]
-  Use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING in
-    example.c, pngtest.c, and applications in the contrib directory.
-  Fixed an out-of-range read in png_user_version_check() (Bug report from
-    Qixue Xiao, CVE-2015-8540).
-  Simplified and future-proofed png_user_version_check().
-  Fixed GCC unsigned int->float warnings. Various versions of GCC
-    seem to generate warnings when an unsigned value is implicitly
-    converted to double. This is probably a GCC bug but this change
-    avoids the issue by explicitly converting to (int) where safe.
-  Free all allocated memory in pngimage. The file buffer cache was left
-    allocated at the end of the program, harmless but it causes memory
-    leak reports from clang.
-  Fixed array size calculations to avoid warnings. At various points
-    in the code the number of elements in an array is calculated using
-    sizeof.  This generates a compile time constant of type (size_t) which
-    is then typically assigned to an (unsigned int) or (int). Some versions
-    of GCC on 64-bit systems warn about the apparent narrowing, even though
-    the same compiler does apparently generate the correct, in-range,
-    numeric constant.  This adds appropriate, safe, casts to make the
-    warnings go away.
-
-Version 1.6.15beta06 [November 6, 2014]
-  Reverted use png_get_libpng_ver(NULL) instead of PNG_LIBPNG_VER_STRING
-    in the manual, example.c, pngtest.c, and applications in the contrib
-    directory.  It was incorrect advice.
-
-Version 1.6.15beta07 [November 7, 2014]
-  Removed #ifdef PNG_16BIT_SUPPORTED/#endif around png_product2(); it is
-    needed by png_reciprocal2().
-  Added #ifdef PNG_16BIT_SUPPORTED/#endif around png_log16bit() and
-    png_do_swap().
-  Changed all "#endif /* PNG_FEATURE_SUPPORTED */" to "#endif /* FEATURE */"
-
-Version 1.6.15beta08 [November 8, 2014]
-  More housecleaning in *.h
-
-Version 1.6.15rc01 [November 13, 2014]
-
-Version 1.6.15rc02 [November 14, 2014]
-  The macros passed in the command line to Borland make were ignored if
-    similarly-named macros were already defined in makefiles. This behavior
-    is different from POSIX make and other make programs.  Surround the
-    macro definitions with ifndef guards (Cosmin).
-
-Version 1.6.15rc03 [November 16, 2014]
-  Added "-D_CRT_SECURE_NO_WARNINGS" to CFLAGS in scripts/makefile.vcwin32.
-  Removed the obsolete $ARCH variable from scripts/makefile.darwin.
-
-Version 1.6.15 [November 20, 2014]
-  No changes.
-
-Version 1.6.16beta01 [December 14, 2014]
-  Added ".align 2" to arm/filter_neon.S to support old GAS assemblers that
-    don't do alignment correctly.
-  Revised Makefile.am and scripts/symbols.dfn to work with MinGW/MSYS
-    (Bob Friesenhahn).
-
-Version 1.6.16beta02 [December 15, 2014]
-  Revised Makefile.am and scripts/*.dfn again to work with MinGW/MSYS;
-    renamed scripts/*.dfn to scripts/*.c (John Bowler).
-
-Version 1.6.16beta03 [December 21, 2014]
-  Quiet a "comparison always true" warning in pngstest.c (John Bowler).
-
-Version 1.6.16rc01 [December 21, 2014]
-  Restored a test on width that was removed from png.c at libpng-1.6.9
-    (Bug report by Alex Eubanks, CVE-2015-0973).
-
-Version 1.6.16rc02 [December 21, 2014]
-  Undid the update to pngrutil.c in 1.6.16rc01.
-
-Version 1.6.16rc03 [December 21, 2014]
-  Fixed an overflow in png_combine_row() with very wide interlaced images
-    (Bug report and fix by John Bowler, CVE-2014-9495).
-
-Version 1.6.16 [December 22, 2014]
-  No changes.
-
-Version 1.6.17beta01 [January 29, 2015]
-  Removed duplicate PNG_SAFE_LIMITS_SUPPORTED handling from pngconf.h
-  Corrected the width limit calculation in png_check_IHDR().
-  Removed user limits from pngfix. Also pass NULL pointers to
-    png_read_row to skip the unnecessary row de-interlace stuff.
-  Added testing of png_set_packing() to pngvalid.c
-  Regenerated configure scripts in the *.tar distributions with libtool-2.4.4
-  Implement previously untested cases of libpng transforms in pngvalid.c
-  Fixed byte order in png_do_read_filler() with 16-bit input. Previously
-    the high and low bytes of the filler, from png_set_filler() or from
-    png_set_add_alpha(), were read in the wrong order.
-  Made the check for out-of-range values in png_set_tRNS() detect
-    values that are exactly 2^bit_depth, and work on 16-bit platforms.
-  Merged some parts of libpng-1.6.17beta01 and libpng-1.7.0beta47.
-  Added #ifndef __COVERITY__ where needed in png.c, pngrutil.c and
-    pngset.c to avoid warnings about dead code.
-  Added "& 0xff" to many instances of expressions that are typecast
-    to (png_byte), to avoid Coverity warnings.
-
-Version 1.6.17beta02 [February 7, 2015]
-  Work around one more Coverity-scan dead-code warning.
-  Do not build png_product2() when it is unused.
-
-Version 1.6.17beta03 [February 17, 2015]
-  Display user limits in the output from pngtest.
-  Eliminated the PNG_SAFE_LIMITS macro and restored the 1-million-column
-    and 1-million-row default limits in pnglibconf.dfa, that can be reset
-    by the user at build time or run time.  This provides a more robust
-    defense against DOS and as-yet undiscovered overflows.
-
-Version 1.6.17beta04 [February 21, 2015]
-  Added PNG_WRITE_CUSTOMIZE_COMPRESSION_SUPPORTED macro, on by default.
-  Allow user to call png_get_IHDR() with NULL arguments (Reuben Hawkins).
-  Rebuilt configure scripts with automake-1.15 and libtool-2.4.6
-
-Version 1.6.17beta05 [February 25, 2015]
-  Restored compiling of png_reciprocal2 with PNG_NO_16BIT.
-
-Version 1.6.17beta06 [February 27, 2015]
-  Moved png_set_filter() prototype into a PNG_WRITE_SUPPORTED block
-    of png.h.
-  Avoid runtime checks when converting integer to png_byte with
-    Visual Studio (Sergey Kosarevsky)
-
-Version 1.6.17rc01 [March 4, 2015]
-  No changes.
-
-Version 1.6.17rc02 [March 9, 2015]
-  Removed some comments that the configure script did not handle
-    properly from scripts/pnglibconf.dfa and pnglibconf.h.prebuilt.
-  Free the unknown_chunks structure even when it contains no data.
-
-Version 1.6.17rc03 [March 12, 2015]
-  Updated CMakeLists.txt to add OSX framework, change YES/NO to ON/OFF
-    for consistency, and remove some useless tests (Alexey Petruchik).
-
-Version 1.6.17rc04 [March 16, 2015]
-  Remove pnglibconf.h, pnglibconf.c, and pnglibconf.out instead of
-    pnglibconf.* in "make clean" (Cosmin).
-  Fix bug in calculation of maxbits, in png_write_sBIT, introduced
-    in libpng-1.6.17beta01 (John Bowler).
-
-Version 1.6.17rc05 [March 21, 2015]
-  Define PNG_FILTER_* and PNG_FILTER_VALUE_* in png.h even when WRITE
-    is not supported (John Bowler).  This fixes an error introduced in
-    libpng-1.6.17beta06.
-  Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
-    the Coverity scan without them.
-
-Version 1.6.17rc06 [March 23, 2015]
-  Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
-  Reformatted some "&0xff" instances to "& 0xff".
-  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
-    value was wrong.  It's not clear if this affected the final stored
-    value; in the obvious code path the upper and lower 8-bits of the
-    alpha value were identical and the alpha was truncated to 8-bits
-    rather than dividing by 257 (John Bowler).
-
-Version 1.6.17 [March 26, 2015]
-  No changes.
-
-Version 1.6.18beta01 [April 1, 2015]
-  Removed PNG_SET_CHUNK_[CACHE|MALLOC]_LIMIT_SUPPORTED macros.  They
-    have been combined with PNG_SET_USER_LIMITS_SUPPORTED (resolves
-    bug report by Andrew Church).
-  Fixed rgb_to_gray checks and added tRNS checks to pngvalid.c.  This
-    fixes some arithmetic errors that caused some tests to fail on
-    some 32-bit platforms (Bug reports by Peter Breitenlohner [i686]
-    and Petr Gajdos [i586]).
-
-Version 1.6.18beta02 [April 26, 2015]
-  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
-    (Bug report by Viktor Szakats).
-
-Version 1.6.18beta03 [May 6, 2015]
-  Replaced "unexpected" with an integer (0xabadca11) in pngset.c
-    where a long was expected, to avoid a compiler warning when PNG_DEBUG > 1.
-  Added contrib/examples/simpleover.c, to demonstrate how to handle
-    alpha compositing of multiple images, using the "simplified API"
-    and an example PNG generation tool, contrib/examples/genpng.c
-    (John Bowler).
-
-Version 1.6.18beta04 [May 20, 2015]
-  PNG_RELEASE_BUILD replaces tests where the code depended on the build base
-    type and can be defined on the command line, allowing testing in beta
-    builds (John Bowler).
-  Avoid Coverity issue 80858 (REVERSE NULL) in pngtest.c PNG_DEBUG builds.
-  Avoid a harmless potential integer overflow in png_XYZ_from_xy() (Bug
-    report from Christopher Ferris).
-
-Version 1.6.18beta05 [May 31, 2015]
-  Backport filter selection code from libpng-1.7.0beta51, to combine
-    sub_row, up_row, avg_row, and paeth_row into try_row and tst_row.
-  Changed png_voidcast(), etc., to voidcast(), etc., in contrib/tools/pngfix.c
-    to avoid confusion with the libpng private macros.
-  Fixed old cut&paste bug in the weighted filter selection code in
-    pngwutil.c, introduced in libpng-0.95, March 1997.
-
-Version 1.6.18beta06 [June 1, 2015]
-  Removed WRITE_WEIGHTED_FILTERED code, to save a few kbytes of the
-    compiled library size. It never worked properly and as far as we can
-    tell, no one uses it. The png_set_filter_heuristics() and
-    png_set_filter_heuristics_fixed() APIs are retained but deprecated
-    and do nothing.
-
-Version 1.6.18beta07 [June 6, 2015]
-  Removed non-working progressive reader 'skip' function. This
-    function has apparently never been used. It was implemented
-    to support back-door modification of png_struct in libpng-1.4.x
-    but (because it does nothing and cannot do anything) was apparently
-    never tested (John Bowler).
-  Fixed cexcept.h in which GCC 5 now reports that one of the auto
-    variables in the Try macro needs to be volatile to prevent value
-    being lost over the setjmp (John Bowler).
-  Fixed NO_WRITE_FILTER and -Wconversion build breaks (John Bowler).
-  Fix g++ build breaks (John Bowler).
-  Quieted some Coverity issues in pngfix.c, png-fix-itxt.c, pngvalid.c,
-    pngstest.c, and pngimage.c. Most seem harmless, but png-fix-itxt
-    would only work with iTXt chunks with length 255 or less.
-  Added #ifdef's to contrib/examples programs so people don't try
-    to compile them without the minimum required support enabled
-    (suggested by Flavio Medeiros).
-
-Version 1.6.18beta08 [June 30, 2015]
-  Eliminated the final two Coverity defects (insecure temporary file
-    handling in contrib/libtests/pngstest.c; possible overflow of
-    unsigned char in contrib/tools/png-fix-itxt.c). To use the "secure"
-    file handling, define PNG_USE_MKSTEMP, otherwise "tmpfile()" will
-    be used.
-  Removed some unused WEIGHTED_FILTER macros from png.h and pngstruct.h
-
-Version 1.6.18beta09 [July 5, 2015]
-  Removed some useless typecasts from contrib/tools/png-fix-itxt.c
-  Fixed a new signed-unsigned comparison in pngrtran.c (Max Stepin).
-  Replaced arbitrary use of 'extern' with #define PNG_LINKAGE_*.  To
-    preserve API compatibility, the new defines all default to "extern"
-    (requested by Jan Nijtmans).
-
-Version 1.6.18rc01 [July 9, 2015]
-  Belatedly added Mans Rullgard and James Yu to the list of Contributing
-    Authors.
-
-Version 1.6.18rc02 [July 12, 2015]
-  Restored unused FILTER_HEURISTIC macros removed at libpng-1.6.18beta08
-    to png.h to avoid compatibility warnings.
-
-Version 1.6.18rc03 [July 15, 2015]
-  Minor changes to the man page
-
-Version 1.6.18 [July 23, 2015]
-  No changes.
-
-Version 1.6.19beta01 [July 30, 2015]
-  Updated obsolete information about the simplified API macros in the
-    manual pages (Bug report by Arc Riley).
-  Avoid potentially dereferencing NULL info_ptr in png_info_init_3().
-  Rearranged png.h to put the major sections in the same order as
-    in libpng17.
-  Eliminated unused PNG_COST_SHIFT, PNG_WEIGHT_SHIFT, PNG_COST_FACTOR, and
-    PNG_WEIGHT_FACTOR macros.
-  Suppressed some warnings from the Borland C++ 5.5.1/5.82 compiler
-    (Bug report by Viktor Szakats).  Several warnings remain and are
-    unavoidable, where we test for overflow.
-  Fixed potential leak of png_pixels in contrib/pngminus/pnm2png.c
-  Fixed uninitialized variable in contrib/gregbook/rpng2-x.c
-
-Version 1.6.19beta02 [August 19, 2015]
-  Moved config.h.in~ from the "libpng_autotools_files" list to the
-    "libpng_autotools_extra" list in autogen.sh because it was causing a
-    false positive for missing files (bug report by Robert C. Seacord).
-  Removed unreachable "break" statements in png.c, pngread.c, and pngrtran.c
-    to suppress clang warnings (Bug report by Viktor Szakats).
-  Fixed some bad links in the man page.
-  Changed "n bit" to "n-bit" in comments.
-  Added signed/unsigned 16-bit safety net. This removes the dubious
-    0x8000 flag definitions on 16-bit systems. They aren't supported
-    yet the defs *probably* work, however it seems much safer to do this
-    and be advised if anyone, contrary to advice, is building libpng 1.6
-    on a 16-bit system. It also adds back various switch default clauses
-    for GCC; GCC errors out if they are not present (with an appropriately
-    high level of warnings).
-  Safely convert num_bytes to a png_byte in png_set_sig_bytes() (Robert
-    Seacord).
-  Fixed the recently reported 1's complement security issue by replacing
-    the value that is illegal in the PNG spec, in both signed and unsigned
-    values, with 0. Illegal unsigned values (anything greater than or equal
-    to  0x80000000) can still pass through, but since these are not illegal
-    in ANSI-C (unlike 0x80000000 in the signed case) the checking that
-    occurs later can catch them (John Bowler).
-
-Version 1.6.19beta03 [September 26, 2015]
-  Fixed png_save_int_32 when int is not 2's complement (John Bowler).
-  Updated libpng16 with all the recent test changes from libpng17,
-    including changes to pngvalid.c to ensure that the original,
-    distributed, version of contrib/visupng/cexcept.h can be used
-    (John Bowler).
-  pngvalid contains the correction to the use of SAVE/STORE_
-    UNKNOWN_CHUNKS; a bug revealed by changes in libpng 1.7. More
-    tests contain the --strict option to detect warnings and the
-    pngvalid-standard test has been corrected so that it does not
-    turn on progressive-read. There is a separate test which does
-    that. (John Bowler)
-  Also made some signed/unsigned fixes.
-  Make pngstest error limits version specific. Splitting the machine
-    generated error structs out to a file allows the values to be updated
-    without changing pngstest.c itself. Since libpng 1.6 and 1.7 have
-    slightly different error limits this simplifies maintenance. The
-    makepngs.sh script has also been updated to more accurately reflect
-    current problems in libpng 1.7 (John Bowler).
-  Incorporated new test PNG files into make check.  tests/pngstest-*
-    are changed so that the new test files are divided into 8 groups by
-    gamma and alpha channel.  These tests have considerably better code
-    and pixel-value coverage than contrib/pngsuite; however,coverage is
-    still incomplete (John Bowler).
-  Removed the '--strict' in 1.6 because of the double-gamma-correction
-    warning, updated pngstest-errors.h for the errors detected with the
-    new contrib/testspngs PNG test files (John Bowler).
-
-Version 1.6.19beta04 [October 15, 2015]
-  Worked around rgb-to-gray issues in libpng 1.6.  The previous
-    attempts to ignore the errors in the code aren't quite enough to
-    deal with the 'channel selection' encoding added to libpng 1.7; abort.
-    pngvalid.c is changed to drop this encoding in prior versions.
-  Fixed 'pow' macros in pngvalid.c. It is legal for 'pow' to be a
-    macro, therefore the argument list cannot contain preprocessing
-    directives.  Make sure pow is a function where this happens. This is
-    a minimal safe fix, the issue only arises in non-performance-critical
-    code (bug report by Curtis Leach, fix by John Bowler).
-  Added sPLT support to pngtest.c
-
-Version 1.6.19rc01 [October 23, 2015]
-  No changes.
-
-Version 1.6.19rc02 [October 31, 2015]
-  Prevent setting or writing over-length PLTE chunk (Cosmin Truta).
-  Silently truncate over-length PLTE chunk while reading.
-  Libpng incorrectly calculated the output rowbytes when the application
-    decreased either the number of channels or the bit depth (or both) in
-    a user transform.  This was safe; libpng overallocated buffer space
-   (potentially by quite a lot; up to 4 times the amount required) but,
-   from 1.5.4 on, resulted in a png_error (John Bowler).
-
-Version 1.6.19rc03 [November 3, 2015]
-  Fixed some inconsequential cut-and-paste typos in png_set_cHRM_XYZ_fixed().
-  Clarified COPYRIGHT information to state explicitly that versions
-    are derived from previous versions.
-  Removed much of the long list of previous versions from png.h and
-    libpng.3.
-
-Version 1.6.19rc04 [November 5, 2015]
-  Fixed new bug with CRC error after reading an over-length palette
-    (bug report by Cosmin Truta) (CVE-2015-8126).
-
-Version 1.6.19 [November 12, 2015]
-  Cleaned up coding style in png_handle_PLTE().
-
-Version 1.6.20beta01 [November 20, 2015]
-  Avoid potential pointer overflow/underflow in png_handle_sPLT() and
-    png_handle_pCAL() (Bug report by John Regehr).
-
-Version 1.6.20beta02 [November 23, 2015]
-  Fixed incorrect implementation of png_set_PLTE() that uses png_ptr
-    not info_ptr, that left png_set_PLTE() open to the CVE-2015-8126
-    vulnerability.  Fixes CVE-2015-8472.
-
-Version 1.6.20beta03 [November 24, 2015]
-  Backported tests from libpng-1.7.0beta69.
-
-Version 1.6.20rc01 [November 26, 2015]
-  Fixed an error in handling of bad zlib CMINFO field in pngfix, found by
-    American Fuzzy Lop, reported by Brian Carpenter.  inflate() doesn't
-    immediately fault a bad CMINFO field; instead a 'too far back' error
-    happens later (at least some times).  pngfix failed to limit CMINFO to
-    the allowed values but then assumed that window_bits was in range,
-    triggering an assert. The bug is mostly harmless; the PNG file cannot
-    be fixed.
-
-Version 1.6.20rc02 [November 29, 2015]
-  In libpng 1.6 zlib initialization was changed to use the window size
-    in the zlib stream, not a fixed value. This causes some invalid images,
-    where CINFO is too large, to display 'correctly' if the rest of the
-    data is valid.  This provides a workaround for zlib versions where the
-    error arises (ones that support the API change to use the window size
-    in the stream).
-
-Version 1.6.20 [December 3, 2015]
-  No changes.
-
-Version 1.6.21beta01 [December 11, 2015]
-  Fixed syntax "$(command)" in tests/pngstest that some shells other than
-    bash could not parse (Bug report by Nelson Beebe). Use `command` instead.
-
-Version 1.6.21beta02 [December 14, 2015]
-  Moved png_check_keyword() from pngwutil.c to pngset.c
-  Removed LE/BE dependencies in pngvalid, to 'fix' the current problem
-    in the BigEndian tests by not testing it, making the BE code the same 
-    as the LE version.
-  Fixes to pngvalid for various reduced build configurations (eliminate unused
-    statics) and a fix for the case in rgb_to_gray when the digitize option
-    reduces graylo to 0, producing a large error.
-
-Version 1.6.21beta03 [December 18, 2015]
-  Widened the 'limit' check on the internally calculated error limits in
-    the 'DIGITIZE' case (the code used prior to 1.7 for rgb_to_gray error
-    checks) and changed the check to only operate in non-release builds
-    (base build type not RC or RELEASE.)
-  Fixed undefined behavior in pngvalid.c, undefined because
-    (png_byte) << shift is undefined if it changes the signed bit
-    (because png_byte is promoted to int). The libpng exported functions
-    png_get_uint_32 and png_get_uint_16 handle this. (Bug reported by
-    David Drysdale as a result of reports from UBSAN in clang 3.8).
-  This changes pngvalid to use BE random numbers; this used to produce
-    errors but these should not be fixed as a result of the previous changes.
-
-Version 1.6.21rc01 [January 4, 2016]
-  In projects/vstudio, combined readme.txt and WARNING into README.txt
-
-Version 1.6.21rc02 [January 7, 2016]
-  Relocated assert() in contrib/tools/pngfix.c, bug found by American
-    Fuzzy Lop, reported by Brian Carpenter.
-  Marked 'limit' UNUSED in transform_range_check().  This only affects
-    release builds.
-
-Version 1.6.21 [January 15, 2016]
-  Worked around a false-positive Coverity issue in pngvalid.c.
-
-Version 1.6.22beta01 [January 23, 2016]
-  Changed PNG_USE_MKSTEMP to __COVERITY__ to select alternate
-    "tmpfile()" implementation in contrib/libtests/pngstest.c
-  Fixed NO_STDIO build of pngunknown.c to skip calling png_init_io()
-    if there is no stdio.h support.
-  Added a png_image_write_to_memory() API and a number of assist macros
-    to allow an application that uses the simplified API write to bypass
-    stdio and write directly to memory.
-  Added some warnings (png.h) and some check code to detect *possible*
-    overflow in the ROW_STRIDE and simplified image SIZE macros.  This
-    disallows image width/height/format that *might* overflow.  This is
-    a quiet API change that limits in-memory image size (uncompressed) to
-    less than 4GByte and image row size (stride) to less than 2GByte.
-  Revised workaround for false-positive Coverity issue in pngvalid.c.
-
-Version 1.6.22beta02 [February 8, 2016]
-  Only use exit(77) in configure builds.
-  Corrected error in PNG_IMAGE_PNG_SIZE_MAX. This new macro underreported
-    the palette size because it failed to take into account that the memory
-    palette has to be expanded to full RGB when it is written to PNG.
-  Updated CMakeLists.txt, added supporting scripts/gen*.cmake.in
-    and test.cmake.in (Roger Leigh).
-  Relaxed limit checks on gamma values in pngrtran.c. As suggested in
-    the comments gamma values outside the range currently permitted
-    by png_set_alpha_mode are useful for HDR data encoding.  These values
-    are already permitted by png_set_gamma so it is reasonable caution to
-    extend the png_set_alpha_mode range as HDR imaging systems are starting
-    to emerge.
-
-Version 1.6.22beta03 [March 9, 2016]
-  Added a common-law trademark notice and export control information
-    to the LICENSE file, png.h, and the man page.
-  Restored "& 0xff" in png_save_uint_16() and png_save_uint_32() that
-    were accidentally removed from libpng-1.6.17. 
-  Changed PNG_INFO_cHNK and PNG_FREE_cHNK from 0xnnnn to 0xnnnnU in png.h
-    (Robert C. Seacord).
-  Removed dubious "#if INT_MAX" test from png.h that was added to
-    libpng-1.6.19beta02 (John Bowler).
-  Add ${INCLUDES} in scripts/genout.cmake.in (Bug report by Nixon Kwok).
-  Updated LICENSE to say files in the contrib directory are not
-    necessarily under the libpng license, and that some makefiles have
-    other copyright owners.
-  Added INTEL-SSE2 support (Mike Klein and Matt Sarett, Google, Inc.).
-  Made contrib/libtests/timepng more robust.  The code no longer gives
-    up/fails on invalid PNG data, it just skips it (with error messages).
-    The code no longer fails on PNG files with data beyond IEND.  Options
-    exist to use png_read_png (reading the whole image, not by row) and, in
-    that case, to apply any of the supported transforms.  This makes for
-    more realistic testing; the decoded data actually gets used in a
-    meaningful fashion (John Bowler).
-  Fixed some misleading indentation (Krishnaraj Bhat).
-
-Version 1.6.22beta04 [April 5, 2016]
-  Force GCC compilation to C89 if needed (Dagobert Michelsen).
-  SSE filter speed improvements for bpp=3:
-    memcpy-free implementations of load3() / store3().
-    call load3() only when needed at the end of a scanline.
-
-Version 1.6.22beta05 [April 27, 2016]
-  Added PNG_FAST_FILTERS macro (defined as
-    PNG_FILTER_NONE|PNG_FILTER_SUB|PNG_FILTER_UP).
-  Various fixes for contrib/libtests/timepng.c
-  Moved INTEL-SSE code from pngpriv.h into contrib/intel/intel_sse.patch.
-  Fixed typo (missing underscore) in #define PNG_READ_16_TO_8_SUPPORTED
-    (Bug report by Y.Ohashik).
-
-Version 1.6.22beta06 [May 5, 2016]
-  Rebased contrib/intel_sse.patch.
-  Quieted two Coverity issues in contrib/libtests/timepng.c.
-  Fixed issues with scripts/genout.cmake.in (David Capello, Nixon Kwok):
-    Added support to use multiple directories in ZLIBINCDIR variable,
-    Fixed CMAKE_C_FLAGS with multiple values when genout is compiled on MSVC,
-    Fixed pnglibconf.c compilation on OS X including the sysroot path.
-
-Version 1.6.22rc01 [May 14, 2016]
-  No changes.
-
-Version 1.6.22rc02 [May 16, 2016]
-  Removed contrib/timepng from default build; it does not build on platforms
-    that don't supply clock_gettime().
-
-Version 1.6.22rc03 [May 17, 2016]
-  Restored contrib/timepng to default build but check for the presence
-    of clock_gettime() in configure.ac and Makefile.am.
-
-Version 1.6.22 [May 26, 2016]
-  No changes.
-
-Version 1.6.23beta01 [May 29, 2016]
-  Stop a potential memory leak in png_set_tRNS() (Bug report by Ted Ying).
-  Fixed the progressive reader to handle empty first IDAT chunk properly
-    (patch by Timothy Nikkel).  This bug was introduced in libpng-1.6.0 and
-    only affected the libpng16 branch.
-  Added tests in pngvalid.c to check zero-length IDAT chunks in various
-    positions.  Fixed the sequential reader to handle these more robustly
-    (John Bowler).
-
-Version 1.6.23rc01 [June 2, 2016]
-  Corrected progressive read input buffer in pngvalid.c. The previous version
-    the code invariably passed just one byte at a time to libpng.  The intent
-    was to pass a random number of bytes in the range 0..511.
-  Moved sse2 prototype from pngpriv.h to contrib/intel/intel_sse.patch.
-  Added missing ")" in pngerror.c (Matt Sarrett).
-
-Version 1.6.23rc02 [June 4, 2016]
-  Fixed undefined behavior in png_push_save_buffer(). Do not call
-    memcpy() with a null source, even if count is zero (Leon Scroggins III).
-
-Version 1.6.23 [June 9, 2016]
-  Fixed bad link to RFC2083 in png.5 (Nikola Forro).
-
-Version 1.6.24beta01 [June 11, 2016]
-  Avoid potential overflow of the PNG_IMAGE_SIZE macro.  This macro
-    is not used within libpng, but is used in some of the examples.
-
-Version 1.6.24beta02 [June 23, 2016]
-  Correct filter heuristic overflow handling. This was broken when the
-    write filter code was moved out-of-line; if there is a single filter and
-    the heuristic sum overflows the calculation of the filtered line is not
-    completed.  In versions prior to 1.6 the code was duplicated in-line
-    and the check not performed, so the filter operation completed; however,
-    in the multi-filter case where the sum is performed the 'none' filter would
-    be selected if all the sums overflowed, even if it wasn't in the filter
-    list.  The fix to the first problem is simply to provide PNG_SIZE_MAX as
-    the current lmins sum value; this means the sum can never exceed it and
-    overflows silently.  A reasonable compiler that does choose to inline
-    the code will simply eliminate the sum check.
-  The fix to the second problem is to use high precision arithmetic (this is
-    implemented in 1.7), however a simple safe fix here is to chose the lowest
-    numbered filter in the list from png_set_filter (this only works if the
-    first problem is also fixed) (John Bowler).
-  Use a more efficient absolute value calculation on SSE2 (Matthieu Darbois).
-  Fixed the case where PNG_IMAGE_BUFFER_SIZE can overflow in the application
-    as a result of the application using an increased 'row_stride'; previously
-    png_image_finish_read only checked for overflow on the base calculation of
-    components.  (I.e. it checked for overflow of a 32-bit number on the total
-    number of pixel components in the output format, not the possibly padded row
-    length and not the number of bytes, which for linear formats is twice the
-    number of components.)
-  MSVC does not like '-(unsigned)', so replaced it with 0U-(unsigned)
-  MSVC does not like (uInt) = -(unsigned) (i.e. as an initializer), unless
-    the conversion is explicitly invoked by a cast.
-  Put the SKIP definition in the correct place. It needs to come after the
-    png.h include (see all the other .c files in contrib/libtests) because it
-    depends on PNG_LIBPNG_VER.
-  Removed the three compile warning options from the individual project
-    files into the zlib.props globals.  It increases the warning level from 4
-    to All and adds a list of the warnings that need to be turned off.  This is
-    semi-documentary; the intent is to tell libpng users which warnings have
-    been examined and judged non-fixable at present.  The warning about
-    structure padding is fixable, but it would be a signficant change (moving
-    structure members around).
-
-Version 1.6.24beta03 [July 4, 2016]
-  Optimized absolute value calculation in filter selection, similar to
-    code in the PAETH decoder in pngrutil.c. Build with PNG_USE_ABS to
-    use this.
-  Added pngcp to the build together with a pngcp.dfa configuration test.
-  Added high resolution timing to pngcp.
-  Added "Common linking failures" section to INSTALL.
-  Relocated misplaced #endif in png.c sRGB profile checking.
-  Fixed two Coverity issues in pngcp.c.
-
-Version 1.6.24beta04 [July 8, 2016]
-  Avoid filter-selection heuristic sum calculations in cases where only one
-    filter is a candidate for selection. This trades off code size (added
-    private png_setup_*_row_only() functions) for speed.
-
-Version 1.6.24beta05 [July 13, 2016]
-  Fixed some indentation to comply with our coding style.
-  Added contrib/tools/reindent.
-
-Version 1.6.24beta06 [July 18, 2016]
-  Fixed more indentation to comply with our coding style.
-  Eliminated unnecessary tests of boolean png_isaligned() vs 0.
-
-Version 1.6.24rc01 [July 25, 2016]
-  No changes.
-
-Version 1.6.24rc02 [August 1, 2016]
-  Conditionally compile SSE2 headers in contrib/intel/intel_sse.patch
-  Conditionally compile png_decompress_chunk().
-
-Version 1.6.24rc03 [August 2, 2016]
-  Conditionally compile ARM_NEON headers in pngpriv.h
-  Updated contrib/intel/intel_sse.patch
-
-Version 1.6.24[August 4, 2016]
-  No changes.
-
-Send comments/corrections/commendations to png-mng-implement at lists.sf.net
-(subscription required; visit
-https://lists.sourceforge.net/lists/listinfo/png-mng-implement
-to subscribe)
-or to glennrp at users.sourceforge.net
-
-Glenn R-P
-#endif
diff --git a/CMakeLists.txt b/CMakeLists.txt
deleted file mode 100644
index 186b65a..0000000
--- a/CMakeLists.txt
+++ /dev/null
@@ -1,804 +0,0 @@
-# CMakeLists.txt
-
-# Copyright (C) 2007,2009-2016 Glenn Randers-Pehrson
-# Written by Christian Ehrlicher, 2007
-# Revised by Roger Lowman, 2009-2010
-# Revised by Clifford Yapp, 2011-2012
-# Revised by Roger Leigh, 2016
-
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-cmake_minimum_required(VERSION 2.8.3)
-cmake_policy(VERSION 2.8.3)
-
-# Set MacOSX @rpath usage globally.
-if (POLICY CMP0020)
-  cmake_policy(SET CMP0020 NEW)
-endif(POLICY CMP0020)
-if (POLICY CMP0042)
-  cmake_policy(SET CMP0042 NEW)
-endif(POLICY CMP0042)
-# Use new variable expansion policy.
-if (POLICY CMP0053)
-  cmake_policy(SET CMP0053 NEW)
-endif(POLICY CMP0053)
-if (POLICY CMP0054)
-  cmake_policy(SET CMP0054 NEW)
-endif(POLICY CMP0054)
-
-set(CMAKE_CONFIGURATION_TYPES "Release;Debug;MinSizeRel;RelWithDebInfo")
-
-project(libpng C)
-enable_testing()
-
-set(PNGLIB_MAJOR 1)
-set(PNGLIB_MINOR 6)
-set(PNGLIB_RELEASE 24)
-set(PNGLIB_NAME libpng${PNGLIB_MAJOR}${PNGLIB_MINOR})
-set(PNGLIB_VERSION ${PNGLIB_MAJOR}.${PNGLIB_MINOR}.${PNGLIB_RELEASE})
-
-# needed packages
-find_package(ZLIB REQUIRED)
-include_directories(${ZLIB_INCLUDE_DIR})
-
-if(NOT WIN32)
-  find_library(M_LIBRARY
-    NAMES m
-    PATHS /usr/lib /usr/local/lib
-  )
-  if(NOT M_LIBRARY)
-    message(STATUS "math lib 'libm' not found; floating point support disabled")
-  endif()
-else()
-  # not needed on windows
-  set(M_LIBRARY "")
-endif()
-
-# COMMAND LINE OPTIONS
-option(PNG_SHARED "Build shared lib" ON)
-option(PNG_STATIC "Build static lib" ON)
-option(PNG_TESTS  "Build libpng tests" ON)
-
-# Many more configuration options could be added here
-option(PNG_FRAMEWORK "Build OS X framework" OFF)
-option(PNG_DEBUG     "Build with debug output" OFF)
-option(PNGARG        "Disable ANSI-C prototypes" OFF)
-
-set(PNG_PREFIX "" CACHE STRING "Prefix to add to the API function names")
-set(DFA_XTRA "" CACHE FILEPATH "File containing extra configuration settings")
-
-# SET LIBNAME
-set(PNG_LIB_NAME png${PNGLIB_MAJOR}${PNGLIB_MINOR})
-
-# to distinguish between debug and release lib
-set(CMAKE_DEBUG_POSTFIX "d")
-
-include(CheckCSourceCompiles)
-option(ld-version-script "Enable linker version script" ON)
-if(ld-version-script AND NOT APPLE)
-  # Check if LD supports linker scripts.
-  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map" "VERS_1 {
-        global: sym;
-        local: *;
-};
-
-VERS_2 {
-        global: sym2;
-                main;
-} VERS_1;
-")
-  set(CMAKE_REQUIRED_FLAGS_SAVE ${CMAKE_REQUIRED_FLAGS})
-  set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS} "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/conftest.map'")
-  check_c_source_compiles("void sym(void) {}
-void sym2(void) {}
-int main(void) {return 0;}
-" HAVE_LD_VERSION_SCRIPT)
-  if(NOT HAVE_LD_VERSION_SCRIPT)
-    set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS_SAVE} "-Wl,-M -Wl,${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
-  check_c_source_compiles("void sym(void) {}
-void sym2(void) {}
-int main(void) {return 0;}
-" HAVE_SOLARIS_LD_VERSION_SCRIPT)
-  endif()
-  set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS_SAVE})
-  file(REMOVE "${CMAKE_CURRENT_BINARY_DIR}/conftest.map")
-endif()
-
-# Find symbol prefix.  Likely obsolete and unnecessary with recent
-# toolchains (it's not done in many other projects).
-function(symbol_prefix)
-  set(SYMBOL_PREFIX)
-
-  execute_process(COMMAND "${CMAKE_C_COMPILER}" "-E" "-"
-                  INPUT_FILE /dev/null
-                  OUTPUT_VARIABLE OUT
-                  RESULT_VARIABLE STATUS)
-
-  if(CPP_FAIL)
-    message(WARNING "Failed to run the C preprocessor")
-  endif()
-
-  string(REPLACE "\n" ";" OUT "${OUT}")
-  foreach(line ${OUT})
-    string(REGEX MATCH "^PREFIX=" found_match "${line}")
-    if(found_match)
-      STRING(REGEX REPLACE "^PREFIX=(.*\)" "\\1" prefix "${line}")
-      string(REGEX MATCH "__USER_LABEL_PREFIX__" found_match "${prefix}")
-      if(found_match)
-        STRING(REGEX REPLACE "(.*)__USER_LABEL_PREFIX__(.*)" "\\1\\2" prefix "${prefix}")
-      endif()
-      set(SYMBOL_PREFIX "${prefix}")
-    endif()
-  endforeach()
-
-    message(STATUS "Symbol prefix: ${SYMBOL_PREFIX}")
-    set(SYMBOL_PREFIX "${SYMBOL_PREFIX}" PARENT_SCOPE)
-endfunction()
-
-if(UNIX)
-  symbol_prefix()
-endif()
-
-find_program(AWK NAMES gawk awk)
-
-include_directories(${CMAKE_CURRENT_BINARY_DIR})
-
-if(NOT AWK)
-  # No awk available to generate sources; use pre-built pnglibconf.h
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt
-                 ${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h)
-  add_custom_target(genfiles) # Dummy
-else()
-  include(CMakeParseArguments)
-  # Generate .chk from .out with awk
-  # generate_chk(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
-  function(generate_chk)
-    set(options)
-    set(oneValueArgs INPUT OUTPUT)
-    set(multiValueArgs DEPENDS)
-    cmake_parse_arguments(_GC "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-    if (NOT _GC_INPUT)
-      message(FATAL_ERROR "Invalid arguments.  generate_out requires input.")
-    endif()
-    if (NOT _GC_OUTPUT)
-      message(FATAL_ERROR "Invalid arguments.  generate_out requires output.")
-    endif()
-
-    add_custom_command(OUTPUT "${_GC_OUTPUT}"
-                       COMMAND "${CMAKE_COMMAND}"
-                               "-DINPUT=${_GC_INPUT}"
-                               "-DOUTPUT=${_GC_OUTPUT}"
-                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/genchk.cmake"
-                       DEPENDS "${_GC_INPUT}" ${_GC_DEPENDS}
-                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
-  endfunction()
-
-  # Generate .out from .c with awk
-  # generate_out(INPUT inputfile OUTPUT outputfile [DEPENDS dep1 [dep2...]])
-  function(generate_out)
-    set(options)
-    set(oneValueArgs INPUT OUTPUT)
-    set(multiValueArgs DEPENDS)
-    cmake_parse_arguments(_GO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-    if (NOT _GO_INPUT)
-      message(FATAL_ERROR "Invalid arguments.  generate_out requires input.")
-    endif()
-    if (NOT _GO_OUTPUT)
-      message(FATAL_ERROR "Invalid arguments.  generate_out requires output.")
-    endif()
-
-    add_custom_command(OUTPUT "${_GO_OUTPUT}"
-                       COMMAND "${CMAKE_COMMAND}"
-                               "-DINPUT=${_GO_INPUT}"
-                               "-DOUTPUT=${_GO_OUTPUT}"
-                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/genout.cmake"
-                       DEPENDS "${_GO_INPUT}" ${_GO_DEPENDS}
-                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
-  endfunction()
-
-  # Generate specific source file with awk
-  # generate_source(OUTPUT outputfile [DEPENDS dep1 [dep2...]])
-  function(generate_source)
-    set(options)
-    set(oneValueArgs OUTPUT)
-    set(multiValueArgs DEPENDS)
-    cmake_parse_arguments(_GSO "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-    if (NOT _GSO_OUTPUT)
-      message(FATAL_ERROR "Invalid arguments.  generate_source requires output.")
-    endif()
-
-    add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${_GSO_OUTPUT}"
-                       COMMAND "${CMAKE_COMMAND}"
-                               "-DOUTPUT=${_GSO_OUTPUT}"
-                               -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake"
-                       DEPENDS ${_GSO_DEPENDS}
-                       WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
-  endfunction()
-
-  # Copy file
-  function(generate_copy source destination)
-    add_custom_command(OUTPUT "${destination}"
-                       COMMAND "${CMAKE_COMMAND}" -E remove "${destination}"
-                       COMMAND "${CMAKE_COMMAND}" -E copy "${source}"
-                                                          "${destination}"
-                       DEPENDS "${source}")
-  endfunction()
-
-  # Generate scripts/pnglibconf.h
-  generate_source(OUTPUT "scripts/pnglibconf.c"
-                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
-                          "${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk"
-                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")
-
-  # Generate pnglibconf.c
-  generate_source(OUTPUT "pnglibconf.c"
-                  DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.dfa"
-                          "${CMAKE_CURRENT_SOURCE_DIR}/scripts/options.awk"
-                          "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h")
-
-  if(PNG_PREFIX)
-    set(PNGLIBCONF_H_EXTRA_DEPENDS
-        "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
-        "${CMAKE_CURRENT_SOURCE_DIR}/scripts/macro.lst")
-    set(PNGPREFIX_H_EXTRA_DEPENDS
-        "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out")
-  endif()
-
-  generate_out(INPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
-               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")
-
-  # Generate pnglibconf.h
-  generate_source(OUTPUT "pnglibconf.h"
-                  DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
-                          ${PNGLIBCONF_H_EXTRA_DEPENDS})
-
-  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/intprefix.c"
-               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out"
-               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")
-
-  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/prefix.c"
-               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
-               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
-                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
-                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out")
-
-  # Generate pngprefix.h
-  generate_source(OUTPUT "pngprefix.h"
-                  DEPENDS ${PNGPREFIX_H_EXTRA_DEPENDS})
-
-  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/sym.c"
-               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
-               DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")
-
-  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.c"
-               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
-               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
-                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
-                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/pnglibconf.h.prebuilt")
-
-  generate_out(INPUT "${CMAKE_CURRENT_SOURCE_DIR}/scripts/vers.c"
-               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
-               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/png.h"
-                       "${CMAKE_CURRENT_SOURCE_DIR}/pngconf.h"
-                       "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h")
-
-  generate_chk(INPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
-               OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
-               DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/scripts/checksym.awk"
-                       "${CMAKE_CURRENT_SOURCE_DIR}/scripts/symbols.def")
-
-  add_custom_target(symbol-check DEPENDS
-                    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk")
-
-  generate_copy("${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
-                "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")
-  generate_copy("${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out"
-                "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")
-
-  add_custom_target(genvers DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers")
-  add_custom_target(gensym DEPENDS "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym")
-
-  add_custom_target("genprebuilt"
-                    COMMAND "${CMAKE_COMMAND}"
-                            "-DOUTPUT=scripts/pnglibconf.h.prebuilt"
-                            -P "${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake"
-                    WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
-
-  # A single target handles generation of all generated files.  If
-  # they are dependend upon separately by multiple targets, this
-  # confuses parallel make (it would require a separate top-level
-  # target for each file to track the dependencies properly).
-  add_custom_target(genfiles DEPENDS
-    "${CMAKE_CURRENT_BINARY_DIR}/libpng.sym"
-    "${CMAKE_CURRENT_BINARY_DIR}/libpng.vers"
-    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.c"
-    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
-    "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.out"
-    "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h"
-    "${CMAKE_CURRENT_BINARY_DIR}/scripts/intprefix.out"
-    "${CMAKE_CURRENT_BINARY_DIR}/scripts/pnglibconf.c"
-    "${CMAKE_CURRENT_BINARY_DIR}/scripts/prefix.out"
-    "${CMAKE_CURRENT_BINARY_DIR}/scripts/sym.out"
-    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.chk"
-    "${CMAKE_CURRENT_BINARY_DIR}/scripts/symbols.out"
-    "${CMAKE_CURRENT_BINARY_DIR}/scripts/vers.out")
-endif(NOT AWK)
-
-# OUR SOURCES
-set(libpng_public_hdrs
-  png.h
-  pngconf.h
-  "${CMAKE_CURRENT_BINARY_DIR}/pnglibconf.h"
-)
-set(libpng_private_hdrs
-  pngpriv.h
-  pngdebug.h
-  pnginfo.h
-  pngstruct.h
-)
-if(AWK)
-  list(APPEND libpng_private_hdrs "${CMAKE_CURRENT_BINARY_DIR}/pngprefix.h")
-endif()
-set(libpng_sources
-  ${libpng_public_hdrs}
-  ${libpng_private_hdrs}
-  png.c
-  pngerror.c
-  pngget.c
-  pngmem.c
-  pngpread.c
-  pngread.c
-  pngrio.c
-  pngrtran.c
-  pngrutil.c
-  pngset.c
-  pngtrans.c
-  pngwio.c
-  pngwrite.c
-  pngwtran.c
-  pngwutil.c
-)
-set(pngtest_sources
-  pngtest.c
-)
-set(pngvalid_sources
-  contrib/libtests/pngvalid.c
-)
-set(pngstest_sources
-  contrib/libtests/pngstest.c
-)
-set(pngunknown_sources
-  contrib/libtests/pngunknown.c
-)
-set(pngimage_sources
-  contrib/libtests/pngimage.c
-)
-set(pngfix_sources
-  contrib/tools/pngfix.c
-)
-set(png_fix_itxt_sources
-  contrib/tools/png-fix-itxt.c
-)
-
-if(MSVC)
-  add_definitions(-D_CRT_SECURE_NO_DEPRECATE)
-endif(MSVC)
-
-if(PNG_DEBUG)
-  add_definitions(-DPNG_DEBUG)
-endif()
-
-# NOW BUILD OUR TARGET
-include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${ZLIB_INCLUDE_DIR})
-
-unset(PNG_LIB_TARGETS)
-
-if(PNG_SHARED)
-  add_library(png SHARED ${libpng_sources})
-  set(PNG_LIB_TARGETS png)
-  set_target_properties(png PROPERTIES OUTPUT_NAME ${PNG_LIB_NAME})
-  add_dependencies(png genfiles)
-  if(MSVC)
-    # msvc does not append 'lib' - do it here to have consistent name
-    set_target_properties(png PROPERTIES PREFIX "lib")
-    set_target_properties(png PROPERTIES IMPORT_PREFIX "lib")
-  endif()
-  target_link_libraries(png ${ZLIB_LIBRARY} ${M_LIBRARY})
-
-  if(UNIX AND AWK)
-    if(HAVE_LD_VERSION_SCRIPT)
-      set_target_properties(png PROPERTIES LINK_FLAGS
-        "-Wl,--version-script='${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
-    elseif(HAVE_SOLARIS_LD_VERSION_SCRIPT)
-      set_target_properties(png PROPERTIES LINK_FLAGS
-        "-Wl,-M -Wl,'${CMAKE_CURRENT_BINARY_DIR}/libpng.vers'")
-    endif()
-  endif()
-endif()
-
-if(PNG_STATIC)
-  # does not work without changing name
-  set(PNG_LIB_NAME_STATIC png_static)
-  add_library(png_static STATIC ${libpng_sources})
-  add_dependencies(png_static genfiles)
-  # MSVC doesn't use a different file extension for shared vs. static
-  # libs.  We are able to change OUTPUT_NAME to remove the _static
-  # for all other platforms.
-  if(NOT MSVC)
-    set_target_properties(png_static PROPERTIES
-      OUTPUT_NAME "${PNG_LIB_NAME}"
-      CLEAN_DIRECT_OUTPUT 1)
-  else()
-    set_target_properties(png_static PROPERTIES
-      OUTPUT_NAME "${PNG_LIB_NAME}_static"
-      CLEAN_DIRECT_OUTPUT 1)
-  endif()
-  list(APPEND PNG_LIB_TARGETS png_static)
-  if(MSVC)
-    # msvc does not append 'lib' - do it here to have consistent name
-    set_target_properties(png_static PROPERTIES PREFIX "lib")
-  endif()
-  target_link_libraries(png_static ${ZLIB_LIBRARY} ${M_LIBRARY})
-endif()
-
-if(PNG_FRAMEWORK)
-  set(PNG_LIB_NAME_FRAMEWORK png_framework)
-  add_library(png_framework SHARED ${libpng_sources})
-  add_dependencies(png_framework genfiles)
-  list(APPEND PNG_LIB_TARGETS png_framework)
-  set_target_properties(png_framework PROPERTIES
-    FRAMEWORK TRUE
-    FRAMEWORK_VERSION ${PNGLIB_VERSION}
-    MACOSX_FRAMEWORK_SHORT_VERSION_STRING ${PNGLIB_MAJOR}.${PNGLIB_MINOR}
-    MACOSX_FRAMEWORK_BUNDLE_VERSION ${PNGLIB_VERSION}
-    MACOSX_FRAMEWORK_IDENTIFIER org.libpng.libpng
-    XCODE_ATTRIBUTE_INSTALL_PATH "@rpath"
-    PUBLIC_HEADER "${libpng_public_hdrs}"
-    OUTPUT_NAME png)
-  target_link_libraries(png_framework ${ZLIB_LIBRARY} ${M_LIBRARY})
-endif()
-
-if(NOT PNG_LIB_TARGETS)
-  message(SEND_ERROR
-    "No library variant selected to build. "
-    "Please enable at least one of the following options: "
-    " PNG_STATIC, PNG_SHARED, PNG_FRAMEWORK")
-endif()
-
-if(PNG_SHARED AND WIN32)
-  set_target_properties(png PROPERTIES DEFINE_SYMBOL PNG_BUILD_DLL)
-endif()
-
-function(png_add_test)
-  set(options)
-  set(oneValueArgs NAME COMMAND)
-  set(multiValueArgs OPTIONS FILES)
-  cmake_parse_arguments(_PAT "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
-
-  if (NOT _PAT_NAME)
-    message(FATAL_ERROR "Invalid arguments.  png_add_test requires name.")
-  endif()
-  if (NOT _PAT_COMMAND)
-    message(FATAL_ERROR "Invalid arguments.  png_add_test requires command.")
-  endif()
-
-  set(TEST_OPTIONS "${_PAT_OPTIONS}")
-  set(TEST_FILES "${_PAT_FILES}")
-
-  configure_file("${CMAKE_CURRENT_SOURCE_DIR}/scripts/test.cmake.in"
-                 "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake" @ONLY)
-  if(CMAKE_MAJOR_VERSION GREATER 2) # have generator expressions
-    add_test(NAME "${_PAT_NAME}"
-             COMMAND "${CMAKE_COMMAND}"
-             "-DLIBPNG=$<TARGET_FILE:png>"
-             "-DTEST_COMMAND=$<TARGET_FILE:${_PAT_COMMAND}>"
-             -P "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake")
-  else() # old 2.x add_test; limited and won't work well on Windows
-    # Note LIBPNG is a dummy value as there are no generator expressions
-    add_test("${_PAT_NAME}" "${CMAKE_COMMAND}"
-             "-DLIBPNG=${CMAKE_CURRENT_BINARY_DIR}/libpng.so"
-             "-DTEST_COMMAND=./${_PAT_COMMAND}"
-             -P "${CMAKE_CURRENT_BINARY_DIR}/tests/${_PAT_NAME}.cmake")
-  endif()
-endfunction()
-
-if(PNG_TESTS AND PNG_SHARED)
-  # Find test PNG files by globbing, but sort lists to ensure
-  # consistency between different filesystems.
-  file(GLOB PNGSUITE_PNGS "${CMAKE_CURRENT_SOURCE_DIR}/contrib/pngsuite/*.png")
-  list(SORT PNGSUITE_PNGS)
-  file(GLOB TEST_PNGS "${CMAKE_CURRENT_SOURCE_DIR}/contrib/testpngs/*.png")
-  list(SORT TEST_PNGS)
-
-  set(PNGTEST_PNG "${CMAKE_CURRENT_SOURCE_DIR}/pngtest.png")
-
-  add_executable(pngtest ${pngtest_sources})
-  target_link_libraries(pngtest png)
-
-  png_add_test(NAME pngtest COMMAND pngtest FILES "${PNGTEST_PNG}")
-
-  add_executable(pngvalid ${pngvalid_sources})
-  target_link_libraries(pngvalid png)
-
-  png_add_test(NAME pngvalid-gamma-16-to-8
-               COMMAND pngvalid OPTIONS --gamma-16-to-8)
-  png_add_test(NAME pngvalid-gamma-alpha-mode
-               COMMAND pngvalid OPTIONS --gamma-alpha-mode)
-  png_add_test(NAME pngvalid-gamma-background
-               COMMAND pngvalid OPTIONS --gamma-background)
-  png_add_test(NAME pngvalid-gamma-expand16-alpha-mode
-               COMMAND pngvalid OPTIONS --gamma-alpha-mode --expand16)
-  png_add_test(NAME pngvalid-gamma-expand16-background
-               COMMAND pngvalid OPTIONS --gamma-background --expand16)
-  png_add_test(NAME pngvalid-gamma-expand16-transform
-               COMMAND pngvalid OPTIONS --gamma-transform --expand16)
-  png_add_test(NAME pngvalid-gamma-sbit
-               COMMAND pngvalid OPTIONS --gamma-sbit)
-  png_add_test(NAME pngvalid-gamma-threshold
-               COMMAND pngvalid OPTIONS --gamma-threshold)
-  png_add_test(NAME pngvalid-gamma-transform
-               COMMAND pngvalid OPTIONS --gamma-transform)
-  png_add_test(NAME pngvalid-progressive-interlace-standard
-               COMMAND pngvalid OPTIONS --standard --progressive-read --interlace)
-  png_add_test(NAME pngvalid-progressive-size
-               COMMAND pngvalid OPTIONS --size --progressive-read)
-  png_add_test(NAME pngvalid-progressive-standard
-               COMMAND pngvalid OPTIONS --standard --progressive-read)
-  png_add_test(NAME pngvalid-standard
-               COMMAND pngvalid OPTIONS --standard)
-  png_add_test(NAME pngvalid-transform
-               COMMAND pngvalid OPTIONS --transform)
-
-  add_executable(pngstest ${pngstest_sources})
-  target_link_libraries(pngstest png)
-
-  foreach(gamma_type 1.8 linear none sRGB)
-    foreach(alpha_type none alpha)
-      set(PNGSTEST_FILES)
-      foreach(test_png ${TEST_PNGS})
-        string(REGEX MATCH ".*-linear[-.].*" TEST_PNG_LINEAR "${test_png}")
-        string(REGEX MATCH ".*-sRGB[-.].*" TEST_PNG_SRGB "${test_png}")
-        string(REGEX MATCH ".*-1.8[-.].*" TEST_PNG_G18 "${test_png}")
-        string(REGEX MATCH ".*-alpha-.*" TEST_PNG_ALPHA "${test_png}")
-
-        set(TEST_PNG_VALID TRUE)
-
-        if(TEST_PNG_ALPHA)
-          if (NOT "${alpha_type}" STREQUAL "alpha")
-            set(TEST_PNG_VALID FALSE)
-          endif()
-        else()
-          if ("${alpha_type}" STREQUAL "alpha")
-            set(TEST_PNG_VALID FALSE)
-          endif()
-        endif()
-
-        if(TEST_PNG_LINEAR)
-          if(NOT "${gamma_type}" STREQUAL "linear")
-            set(TEST_PNG_VALID FALSE)
-          endif()
-        elseif(TEST_PNG_SRGB)
-          if(NOT "${gamma_type}" STREQUAL "sRGB")
-            set(TEST_PNG_VALID FALSE)
-          endif()
-        elseif(TEST_PNG_G18)
-          if(NOT "${gamma_type}" STREQUAL "1.8")
-            set(TEST_PNG_VALID FALSE)
-          endif()
-        else()
-          if(NOT "${gamma_type}" STREQUAL "none")
-            set(TEST_PNG_VALID FALSE)
-          endif()
-        endif()
-
-        if(TEST_PNG_VALID)
-          list(APPEND PNGSTEST_FILES "${test_png}")
-        endif()
-      endforeach()
-      # Should already be sorted, but sort anyway to be certain.
-      list(SORT PNGSTEST_FILES)
-      png_add_test(NAME pngstest-${gamma_type}-${alpha_type}
-                   COMMAND pngstest
-                   OPTIONS --tmpfile "${gamma_type}-${alpha_type}-" --log
-                   FILES ${PNGSTEST_FILES})
-    endforeach()
-  endforeach()
-
-  add_executable(pngunknown ${pngunknown_sources})
-  target_link_libraries(pngunknown png)
-
-  png_add_test(NAME pngunknown-discard COMMAND pngunknown OPTIONS --strict default=discard FILES "${PNGTEST_PNG}")
-  png_add_test(NAME pngunknown-IDAT COMMAND pngunknown OPTIONS --strict default=discard IDAT=save FILES "${PNGTEST_PNG}")
-  png_add_test(NAME pngunknown-if-safe COMMAND pngunknown OPTIONS --strict default=if-safe FILES "${PNGTEST_PNG}")
-  png_add_test(NAME pngunknown-sAPI COMMAND pngunknown OPTIONS --strict bKGD=save cHRM=save gAMA=save all=discard iCCP=save sBIT=save sRGB=save FILES "${PNGTEST_PNG}")
-  png_add_test(NAME pngunknown-save COMMAND pngunknown OPTIONS --strict default=save FILES "${PNGTEST_PNG}")
-  png_add_test(NAME pngunknown-sTER COMMAND pngunknown OPTIONS --strict sTER=if-safe FILES "${PNGTEST_PNG}")
-  png_add_test(NAME pngunknown-vpAg COMMAND pngunknown OPTIONS --strict vpAg=if-safe FILES "${PNGTEST_PNG}")
-
-  add_executable(pngimage ${pngimage_sources})
-  target_link_libraries(pngimage png)
-
-  png_add_test(NAME pngimage-quick COMMAND pngimage OPTIONS --list-combos --log FILES ${PNGSUITE_PNGS})
-  png_add_test(NAME pngimage-full COMMAND pngimage OPTIONS --exhaustive --list-combos --log FILES ${PNGSUITE_PNGS})
-endif()
-
-if(PNG_SHARED)
-  add_executable(pngfix ${pngfix_sources})
-  target_link_libraries(pngfix png)
-  set(PNG_BIN_TARGETS pngfix)
-
-  add_executable(png-fix-itxt ${png_fix_itxt_sources})
-  target_link_libraries(png-fix-itxt ${ZLIB_LIBRARY} ${M_LIBRARY})
-  list(APPEND PNG_BIN_TARGETS png-fix-itxt)
-endif()
-
-# Ensure the CMAKE_LIBRARY_OUTPUT_DIRECTORY is set
-IF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
-  SET(CMAKE_LIBRARY_OUTPUT_DIRECTORY "lib")
-ENDIF(NOT CMAKE_LIBRARY_OUTPUT_DIRECTORY)
-
-# Set a variable with CMake code which:
-# Creates a symlink from src to dest (if possible) or alternatively
-# copies if different.
-macro(CREATE_SYMLINK SRC_FILE DEST_FILE)
-  FILE(REMOVE ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
-  if(WIN32 AND NOT CYGWIN AND NOT MSYS)
-    ADD_CUSTOM_COMMAND(
-        OUTPUT ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}   ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
-        COMMAND ${CMAKE_COMMAND} -E copy_if_different  "${SRC_FILE}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE}
-        COMMAND ${CMAKE_COMMAND} -E copy_if_different  "${SRC_FILE}" ${CMAKE_CURRENT_BINARY_DIR}/${DEST_FILE}
-        DEPENDS ${PNG_LIB_TARGETS}
-        )
-    ADD_CUSTOM_TARGET(${DEST_FILE}_COPY ALL DEPENDS ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE})
-  else(WIN32 AND NOT CYGWIN AND NOT MSYS)
-    get_filename_component(LINK_TARGET "${SRC_FILE}" NAME)
-    execute_process(COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_LIBRARY_OUTPUT_DIRECTORY})
-    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}/${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-    execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${LINK_TARGET}" ${DEST_FILE} WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-  endif(WIN32 AND NOT CYGWIN AND NOT MSYS)
-endmacro()
-
-# Create source generation scripts.
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/genchk.cmake.in
-               ${CMAKE_CURRENT_BINARY_DIR}/scripts/genchk.cmake @ONLY)
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/genout.cmake.in
-               ${CMAKE_CURRENT_BINARY_DIR}/scripts/genout.cmake @ONLY)
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/scripts/gensrc.cmake.in
-               ${CMAKE_CURRENT_BINARY_DIR}/scripts/gensrc.cmake @ONLY)
-
-
-# libpng is a library so default to 'lib'
-if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
-  set(CMAKE_INSTALL_LIBDIR lib)
-endif(NOT DEFINED CMAKE_INSTALL_LIBDIR)
-
-# CREATE PKGCONFIG FILES
-# we use the same files like ./configure, so we have to set its vars
-# Only do this on Windows for Cygwin - the files don't make much sense outside
-# a UNIX look alike
-if(NOT WIN32 OR CYGWIN OR MINGW)
-  set(prefix      ${CMAKE_INSTALL_PREFIX})
-  set(exec_prefix ${CMAKE_INSTALL_PREFIX})
-  set(libdir      ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR})
-  set(includedir  ${CMAKE_INSTALL_PREFIX}/include)
-  set(LIBS        "-lz -lm")
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng.pc.in
-    ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc @ONLY)
-  CREATE_SYMLINK(${PNGLIB_NAME}.pc libpng.pc)
-
-  configure_file(${CMAKE_CURRENT_SOURCE_DIR}/libpng-config.in
-    ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config @ONLY)
-  CREATE_SYMLINK(${PNGLIB_NAME}-config libpng-config)
-endif(NOT WIN32 OR CYGWIN OR MINGW)
-
-# SET UP LINKS
-if(PNG_SHARED)
-  set_target_properties(png PROPERTIES
-#   VERSION 16.${PNGLIB_RELEASE}.1.6.24
-    VERSION 16.${PNGLIB_RELEASE}.0
-    SOVERSION 16
-    CLEAN_DIRECT_OUTPUT 1)
-endif()
-
-# If CMake > 2.4.x, we set a variable used below to export
-# targets to an export file.
-# TODO: Use VERSION_GREATER after our cmake_minimum_required >= 2.6.2
-if(CMAKE_MAJOR_VERSION GREATER 1 AND CMAKE_MINOR_VERSION GREATER 4)
-  set(PNG_EXPORT_RULE EXPORT libpng)
-elseif(CMAKE_MAJOR_VERSION GREATER 2) # future proof
-  set(PNG_EXPORT_RULE EXPORT libpng)
-endif()
-
-# INSTALL
-if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
-  install(TARGETS ${PNG_LIB_TARGETS}
-      ${PNG_EXPORT_RULE}
-      RUNTIME DESTINATION bin
-      LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-      FRAMEWORK DESTINATION ${CMAKE_INSTALL_LIBDIR})
-
-  if(PNG_SHARED)
-    # Create a symlink for libpng.dll.a => libpng16.dll.a on Cygwin
-    if(CYGWIN OR MINGW)
-       get_target_property(BUILD_TARGET_LOCATION png LOCATION_${CMAKE_BUILD_TYPE})
-       CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_IMPORT_LIBRARY_SUFFIX})
-       install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_IMPORT_LIBRARY_SUFFIX}
-         DESTINATION ${CMAKE_INSTALL_LIBDIR})
-    endif(CYGWIN OR MINGW)
-
-    if(NOT WIN32)
-      get_target_property(BUILD_TARGET_LOCATION png LOCATION_${CMAKE_BUILD_TYPE})
-      CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_SHARED_LIBRARY_SUFFIX})
-      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_SHARED_LIBRARY_SUFFIX}
-         DESTINATION ${CMAKE_INSTALL_LIBDIR})
-    endif(NOT WIN32)
-  endif(PNG_SHARED)
-
-  if(PNG_STATIC)
-    if(NOT WIN32 OR CYGWIN OR MINGW)
-      get_target_property(BUILD_TARGET_LOCATION png_static LOCATION_${CMAKE_BUILD_TYPE})
-      CREATE_SYMLINK(${BUILD_TARGET_LOCATION} libpng${CMAKE_STATIC_LIBRARY_SUFFIX})
-      install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng${CMAKE_STATIC_LIBRARY_SUFFIX}
-         DESTINATION ${CMAKE_INSTALL_LIBDIR})
-    endif(NOT WIN32 OR CYGWIN OR MINGW)
- endif()
-endif()
-
-if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL )
-  install(FILES ${libpng_public_hdrs}   DESTINATION include)
-  install(FILES ${libpng_public_hdrs}   DESTINATION include/${PNGLIB_NAME})
-endif()
-if(NOT SKIP_INSTALL_EXECUTABLES AND NOT SKIP_INSTALL_ALL )
-  if(NOT WIN32 OR CYGWIN OR MINGW)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config DESTINATION bin)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
-            DESTINATION bin)
-  endif(NOT WIN32 OR CYGWIN OR MINGW)
-endif()
-
-if(NOT SKIP_INSTALL_PROGRAMS AND NOT SKIP_INSTALL_ALL )
-  install(TARGETS ${PNG_BIN_TARGETS}
-      RUNTIME DESTINATION bin)
-endif()
-
-if(NOT SKIP_INSTALL_FILES AND NOT SKIP_INSTALL_ALL )
-  # Install man pages
-  if(NOT PNG_MAN_DIR)
-    set(PNG_MAN_DIR "share/man")
-  endif()
-  install(FILES libpng.3 libpngpf.3      DESTINATION ${PNG_MAN_DIR}/man3)
-  install(FILES png.5                    DESTINATION ${PNG_MAN_DIR}/man5)
-  # Install pkg-config files
-  if(NOT WIN32 OR CYGWIN OR MINGW)
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libpng.pc
-            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/libpng-config
-            DESTINATION bin)
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}.pc
-            DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
-    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PNGLIB_NAME}-config
-            DESTINATION bin)
-  endif(NOT WIN32 OR CYGWIN OR MINGW)
-endif()
-
-# On versions of CMake that support it, create an export file CMake
-# users can include() to import our targets
-if(PNG_EXPORT_RULE AND NOT SKIP_INSTALL_EXPORT AND NOT SKIP_INSTALL_ALL )
-  install(EXPORT libpng DESTINATION lib/libpng FILE lib${PNG_LIB_NAME}.cmake)
-endif()
-
-# what's with libpng-manual.txt and all the extra files?
-
-# UNINSTALL
-# do we need this?
-
-# DIST
-# do we need this?
-
-# to create msvc import lib for mingw compiled shared lib
-# pexports libpng.dll > libpng.def
-# lib /def:libpng.def /machine:x86
-
diff --git a/INSTALL b/INSTALL
deleted file mode 100644
index eed4dc8..0000000
--- a/INSTALL
+++ /dev/null
@@ -1,402 +0,0 @@
-
-Installing libpng
-
-Contents
-
-   I. Simple installation
-  II. Rebuilding the configure scripts
- III. Using scripts/makefile*
-  IV. Using cmake
-   V. Directory structure
-  VI. Building with project files
- VII. Building with makefiles
-VIII. Configuring libpng for 16-bit platforms
-  IX. Configuring for DOS
-   X. Configuring for Medium Model
-  XI. Prepending a prefix to exported symbols
- XII. Configuring for compiler xxx:
-XIII. Removing unwanted object code
- XIV. Changes to the build and configuration of libpng in libpng-1.5.x
-  XV. Setjmp/longjmp issues
- XVI. Common linking failures
-XVII. Other sources of information about libpng
-
-I. Simple installation
-
-On Unix/Linux and similar systems, you can simply type
-
-    ./configure [--prefix=/path]
-    make check
-    make install
-
-and ignore the rest of this document.  "/path" is the path to the directory
-where you want to install the libpng "lib", "include", and "bin"
-subdirectories.
-
-If you downloaded a GIT clone, you will need to run ./autogen.sh before
-running ./configure, to create "configure" and "Makefile.in" which are
-not included in the GIT repository.
-
-Note that "configure" is only included in the "*.tar" distributions and not
-in the "*.zip" or "*.7z" distributions. If you downloaded one of those
-distributions, see "Building with project files" or "Building with makefiles",
-below.
-
-II. Rebuilding the configure scripts
-
-If configure does not work on your system, or if you have a need to
-change configure.ac or Makefile.am, and you have a reasonably
-up-to-date set of tools, running ./autogen.sh in a git clone before
-running ./configure may fix the problem.  To be really sure that you
-aren't using any of the included pre-built scripts, especially if you
-are building from a tar distribution instead of a git distribution,
-do this:
-
-    ./configure --enable-maintainer-mode
-    make maintainer-clean
-    ./autogen.sh --maintainer --clean
-    ./autogen.sh --maintainer
-    ./configure [--prefix=/path] [other options]
-    make
-    make install
-    make check
-
-III. Using scripts/makefile*
-
-Instead, you can use one of the custom-built makefiles in the
-"scripts" directory
-
-    cp scripts/pnglibconf.h.prebuilt pnglibconf.h
-    cp scripts/makefile.system makefile
-    make test
-    make install
-
-The files that are presently available in the scripts directory
-are listed and described in scripts/README.txt.
-
-Or you can use one of the "projects" in the "projects" directory.
-
-Before installing libpng, you must first install zlib, if it
-is not already on your system.  zlib can usually be found
-wherever you got libpng; otherwise go to http://zlib.net.  You can place
-zlib in the same directory as libpng or in another directory.
-
-If your system already has a preinstalled zlib you will still need
-to have access to the zlib.h and zconf.h include files that
-correspond to the version of zlib that's installed.
-
-If you wish to test with a particular zlib that is not first in the
-standard library search path, put ZLIBLIB, ZLIBINC, CPPFLAGS, LDFLAGS,
-and LD_LIBRARY_PATH in your environment before running "make test"
-or "make distcheck":
-
-ZLIBLIB=/path/to/lib export ZLIBLIB
-ZLIBINC=/path/to/include export ZLIBINC
-CPPFLAGS="-I$ZLIBINC" export CPPFLAGS
-LDFLAGS="-L$ZLIBLIB" export LDFLAGS
-LD_LIBRARY_PATH="$ZLIBLIB:$LD_LIBRARY_PATH" export LD_LIBRARY_PATH
-
-If you are using one of the makefile scripts, put ZLIBLIB and ZLIBINC
-in your environment and type "make ZLIBLIB=$ZLIBLIB ZLIBINC=$ZLIBINC test".
-
-IV. Using cmake
-
-If you want to use "cmake" (see www.cmake.org), type
-
-   cmake . -DCMAKE_INSTALL_PREFIX=/path
-   make
-   make install
-
-As when using the simple configure method described above, "/path" points to
-the installation directory where you want to put the libpng "lib", "include",
-and "bin" subdirectories.
-
-V. Directory structure
-
-You can rename the directories that you downloaded (they
-might be called "libpng-x.y.z" or "libpngNN" and "zlib-1.2.8"
-or "zlib128") so that you have directories called "zlib" and "libpng".
-
-Your directory structure should look like this:
-
-   .. (the parent directory)
-      libpng (this directory)
-          INSTALL (this file)
-          README
-          *.h, *.c  => libpng source files
-          CMakeLists.txt    =>  "cmake" script
-          configuration files:
-             configure.ac, configure, Makefile.am, Makefile.in,
-             autogen.sh, config.guess, ltmain.sh, missing, libpng.pc.in,
-             libpng-config.in, aclocal.m4, config.h.in, config.sub,
-             depcomp, install-sh, mkinstalldirs, test-pngtest.sh
-          contrib
-             arm-neon, conftest, examples, gregbook, libtests, pngminim,
-             pngminus, pngsuite, tools, visupng
-          projects
-             cbuilder5, owatcom, visualc71, vstudio, xcode
-          scripts
-             makefile.*
-             *.def (module definition files)
-             etc.
-          pngtest.png
-          etc.
-      zlib
-          README, *.h, *.c contrib, etc.
-
-If the line endings in the files look funny, you may wish to get the other
-distribution of libpng.  It is available in both tar.gz (UNIX style line
-endings) and zip (DOS style line endings) formats.
-
-VI. Building with project files
-
-If you are building libpng with MSVC, you can enter the
-libpng projects\visualc71 or vstudio directory and follow the instructions
-in README.txt.
-
-Otherwise enter the zlib directory and follow the instructions in zlib/README,
-then come back here and run "configure" or choose the appropriate
-makefile.sys in the scripts directory.
-
-VII. Building with makefiles
-
-Copy the file (or files) that you need from the
-scripts directory into this directory, for example
-
-   MSDOS example: copy scripts\makefile.msc makefile
-                  copy scripts\pnglibconf.h.prebuilt pnglibconf.h
-   UNIX example:  cp scripts/makefile.std makefile
-                  cp scripts/pnglibconf.h.prebuilt pnglibconf.h
-
-Read the makefile to see if you need to change any source or
-target directories to match your preferences.
-
-Then read pnglibconf.dfa to see if you want to make any configuration
-changes.
-
-Then just run "make" which will create the libpng library in
-this directory and "make test" which will run a quick test that reads
-the "pngtest.png" file and writes a "pngout.png" file that should be
-identical to it.  Look for "9782 zero samples" in the output of the
-test.  For more confidence, you can run another test by typing
-"pngtest pngnow.png" and looking for "289 zero samples" in the output.
-Also, you can run "pngtest -m contrib/pngsuite/*.png" and compare
-your output with the result shown in contrib/pngsuite/README.
-
-Most of the makefiles will allow you to run "make install" to
-put the library in its final resting place (if you want to
-do that, run "make install" in the zlib directory first if necessary).
-Some also allow you to run "make test-installed" after you have
-run "make install".
-
-VIII. Configuring libpng for 16-bit platforms
-
-You will want to look into zconf.h to tell zlib (and thus libpng) that
-it cannot allocate more than 64K at a time.  Even if you can, the memory
-won't be accessible.  So limit zlib and libpng to 64K by defining MAXSEG_64K.
-
-IX. Configuring for DOS
-
-For DOS users who only have access to the lower 640K, you will
-have to limit zlib's memory usage via a png_set_compression_mem_level()
-call.  See zlib.h or zconf.h in the zlib library for more information.
-
-X. Configuring for Medium Model
-
-Libpng's support for medium model has been tested on most of the popular
-compilers.  Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
-defined, and FAR gets defined to far in pngconf.h, and you should be
-all set.  Everything in the library (except for zlib's structure) is
-expecting far data.  You must use the typedefs with the p or pp on
-the end for pointers (or at least look at them and be careful).  Make
-note that the rows of data are defined as png_bytepp, which is
-an "unsigned char far * far *".
-
-XI. Prepending a prefix to exported symbols
-
-Starting with libpng-1.6.0, you can configure libpng (when using the
-"configure" script) to prefix all exported symbols by means of the
-configuration option "--with-libpng-prefix=FOO_", where FOO_ can be any
-string beginning with a letter and containing only uppercase
-and lowercase letters, digits, and the underscore (i.e., a C language
-identifier).  This creates a set of macros in pnglibconf.h, so this is
-transparent to applications; their function calls get transformed by
-the macros to use the modified names.
-
-XII. Configuring for compiler xxx:
-
-All includes for libpng are in pngconf.h.  If you need to add, change
-or delete an include, this is the place to do it.
-The includes that are not needed outside libpng are placed in pngpriv.h,
-which is only used by the routines inside libpng itself.
-The files in libpng proper only include pngpriv.h and png.h, which
-in turn includes pngconf.h and, as of libpng-1.5.0, pnglibconf.h.
-As of libpng-1.5.0, pngpriv.h also includes three other private header
-files, pngstruct.h, pnginfo.h, and pngdebug.h, which contain material
-that previously appeared in the public headers.
-
-XIII. Removing unwanted object code
-
-There are a bunch of #define's in pngconf.h that control what parts of
-libpng are compiled.  All the defines end in _SUPPORTED.  If you are
-never going to use a capability, you can change the #define to #undef
-before recompiling libpng and save yourself code and data space, or
-you can turn off individual capabilities with defines that begin with
-PNG_NO_.
-
-In libpng-1.5.0 and later, the #define's are in pnglibconf.h instead.
-
-You can also turn all of the transforms and ancillary chunk capabilities
-off en masse with compiler directives that define
-PNG_NO_READ[or WRITE]_TRANSFORMS, or PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS,
-or all four, along with directives to turn on any of the capabilities that
-you do want.  The PNG_NO_READ[or WRITE]_TRANSFORMS directives disable the
-extra transformations but still leave the library fully capable of reading
-and writing PNG files with all known public chunks. Use of the
-PNG_NO_READ[or WRITE]_ANCILLARY_CHUNKS directive produces a library
-that is incapable of reading or writing ancillary chunks.  If you are
-not using the progressive reading capability, you can turn that off
-with PNG_NO_PROGRESSIVE_READ (don't confuse this with the INTERLACING
-capability, which you'll still have).
-
-All the reading and writing specific code are in separate files, so the
-linker should only grab the files it needs.  However, if you want to
-make sure, or if you are building a stand alone library, all the
-reading files start with "pngr" and all the writing files start with "pngw".
-The files that don't match either (like png.c, pngtrans.c, etc.)
-are used for both reading and writing, and always need to be included.
-The progressive reader is in pngpread.c
-
-If you are creating or distributing a dynamically linked library (a .so
-or DLL file), you should not remove or disable any parts of the library,
-as this will cause applications linked with different versions of the
-library to fail if they call functions not available in your library.
-The size of the library itself should not be an issue, because only
-those sections that are actually used will be loaded into memory.
-
-XIV. Changes to the build and configuration of libpng in libpng-1.5.x
-
-Details of internal changes to the library code can be found in the CHANGES
-file and in the GIT repository logs.  These will be of no concern to the vast
-majority of library users or builders; however, the few who configure libpng
-to a non-default feature set may need to change how this is done.
-
-There should be no need for library builders to alter build scripts if
-these use the distributed build support - configure or the makefiles -
-however, users of the makefiles may care to update their build scripts
-to build pnglibconf.h where the corresponding makefile does not do so.
-
-Building libpng with a non-default configuration has changed completely.
-The old method using pngusr.h should still work correctly even though the
-way pngusr.h is used in the build has been changed; however, library
-builders will probably want to examine the changes to take advantage of
-new capabilities and to simplify their build system.
-
-A. Specific changes to library configuration capabilities
-
-The exact mechanism used to control attributes of API functions has
-changed.  A single set of operating system independent macro definitions
-is used and operating system specific directives are defined in
-pnglibconf.h
-
-As part of this the mechanism used to choose procedure call standards on
-those systems that allow a choice has been changed.  At present this only
-affects certain Microsoft (DOS, Windows) and IBM (OS/2) operating systems
-running on Intel processors.  As before, PNGAPI is defined where required
-to control the exported API functions; however, two new macros, PNGCBAPI
-and PNGCAPI, are used instead for callback functions (PNGCBAPI) and
-(PNGCAPI) for functions that must match a C library prototype (currently
-only png_longjmp_ptr, which must match the C longjmp function.)  The new
-approach is documented in pngconf.h
-
-Despite these changes, libpng 1.5.0 only supports the native C function
-calling standard on those platforms tested so far (__cdecl on Microsoft
-Windows).  This is because the support requirements for alternative
-calling conventions seem to no longer exist.  Developers who find it
-necessary to set PNG_API_RULE to 1 should advise the mailing list
-(png-mng-implement) of this and library builders who use Openwatcom and
-therefore set PNG_API_RULE to 2 should also contact the mailing list.
-
-B. Changes to the configuration mechanism
-
-Prior to libpng-1.5.0 library builders who needed to configure libpng
-had either to modify the exported pngconf.h header file to add system
-specific configuration or had to write feature selection macros into
-pngusr.h and cause this to be included into pngconf.h by defining
-PNG_USER_CONFIG. The latter mechanism had the disadvantage that an
-application built without PNG_USER_CONFIG defined would see the
-unmodified, default, libpng API and thus would probably fail to link.
-
-These mechanisms still work in the configure build and in any makefile
-build that builds pnglibconf.h, although the feature selection macros
-have changed somewhat as described above.  In 1.5.0, however, pngusr.h is
-processed only once, at the time the exported header file pnglibconf.h is
-built.  pngconf.h no longer includes pngusr.h; therefore, pngusr.h is ignored
-after the build of pnglibconf.h and it is never included in an application
-build.
-
-The formerly used alternative of adding a list of feature macros to the
-CPPFLAGS setting in the build also still works; however, the macros will be
-copied to pnglibconf.h and this may produce macro redefinition warnings
-when the individual C files are compiled.
-
-All configuration now only works if pnglibconf.h is built from
-scripts/pnglibconf.dfa.  This requires the program awk.  Brian Kernighan
-(the original author of awk) maintains C source code of that awk and this
-and all known later implementations (often called by subtly different
-names - nawk and gawk for example) are adequate to build pnglibconf.h.
-The Sun Microsystems (now Oracle) program 'awk' is an earlier version
-and does not work; this may also apply to other systems that have a
-functioning awk called 'nawk'.
-
-Configuration options are now documented in scripts/pnglibconf.dfa.  This
-file also includes dependency information that ensures a configuration is
-consistent; that is, if a feature is switched off, dependent features are
-also switched off.  As a recommended alternative to using feature macros in
-pngusr.h a system builder may also define equivalent options in pngusr.dfa
-(or, indeed, any file) and add that to the configuration by setting
-DFA_XTRA to the file name.  The makefiles in contrib/pngminim illustrate
-how to do this, and also illustrate a case where pngusr.h is still required.
-
-After you have built libpng, the definitions that were recorded in
-pnglibconf.h are available to your application (pnglibconf.h is included
-in png.h and gets installed alongside png.h and pngconf.h in your
-$PREFIX/include directory).  Do not edit pnglibconf.h after you have built
-libpng, because than the settings would not accurately reflect the settings
-that were used to build libpng.
-
-XV. Setjmp/longjmp issues
-
-Libpng uses setjmp()/longjmp() for error handling.  Unfortunately setjmp()
-is known to be not thread-safe on some platforms and we don't know of
-any platform where it is guaranteed to be thread-safe.  Therefore, if
-your application is going to be using multiple threads, you should
-configure libpng with PNG_NO_SETJMP in your pngusr.dfa file, with
--DPNG_NO_SETJMP on your compile line, or with
-
-  #undef PNG_SETJMP_SUPPORTED
-
-in your pnglibconf.h or pngusr.h.
-
-Starting with libpng-1.6.0, the library included a "simplified API".
-This requires setjmp/longjmp, so you must either build the library
-with PNG_SETJMP_SUPPORTED defined, or with PNG_SIMPLIFIED_READ_SUPPORTED
-and PNG_SIMPLIFIED_WRITE_SUPPORTED undefined.
-
-XVI. Common linking failures
-
-If your application fails to find libpng or zlib entries while linking:
-
-  Be sure "-lz" appears after "-lpng" on your linking command.
-
-  Be sure you have built libpng, zlib, and your application for the
-  same platform (e.g., 32-bit or 64-bit).
-
-  If you are using the vstudio project, observe the WARNING in
-  project/vstudio/README.txt.
-
-XVII. Other sources of information about libpng:
-
-Further information can be found in the README and libpng-manual.txt
-files, in the individual makefiles, in png.h, and the manual pages
-libpng.3 and png.5.
diff --git a/Makefile.am b/Makefile.am
deleted file mode 100644
index 39e9bde..0000000
--- a/Makefile.am
+++ /dev/null
@@ -1,376 +0,0 @@
-# Makefile.am, the source file for Makefile.in (and hence Makefile), is
-#
-# Copyright (c) 2004-2016 Glenn Randers-Pehrson
-# Last changed in libpng 1.6.22 [(PENDING RELEASE)]
-#
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-PNGLIB_BASENAME= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@
-
-ACLOCAL_AMFLAGS = -I scripts
-
-# test programs - run on make check, make distcheck
-check_PROGRAMS= pngtest pngunknown pngstest pngvalid pngimage
-if HAVE_CLOCK_GETTIME
-check_PROGRAMS += timepng
-endif
-
-# Utilities - installed
-bin_PROGRAMS= pngcp pngfix png-fix-itxt
-
-# This ensures that pnglibconf.h gets built at the start of 'make all' or
-# 'make check', but it does not add dependencies to the individual programs,
-# this is done below.
-#
-# IMPORTANT: always add the object modules of new programs to the list below
-# because otherwise the sequence 'configure; make new-program' will *sometimes*
-# result in the installed (system) pnglibconf.h being used and the result is
-# always wrong and always very confusing.
-BUILT_SOURCES = pnglibconf.h
-
-pngtest_SOURCES = pngtest.c
-pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-
-pngvalid_SOURCES = contrib/libtests/pngvalid.c
-pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-
-pngstest_SOURCES = contrib/libtests/pngstest.c
-pngstest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-
-pngunknown_SOURCES = contrib/libtests/pngunknown.c
-pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-
-pngimage_SOURCES = contrib/libtests/pngimage.c
-pngimage_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-
-timepng_SOURCES = contrib/libtests/timepng.c
-timepng_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-
-pngfix_SOURCES = contrib/tools/pngfix.c
-pngfix_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-
-png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
-
-pngcp_SOURCES = contrib/tools/pngcp.c
-pngcp_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-
-# Generally these are single line shell scripts to run a test with a particular
-# set of parameters:
-TESTS =\
-   tests/pngtest\
-   tests/pngvalid-gamma-16-to-8 tests/pngvalid-gamma-alpha-mode\
-   tests/pngvalid-gamma-background tests/pngvalid-gamma-expand16-alpha-mode\
-   tests/pngvalid-gamma-expand16-background\
-   tests/pngvalid-gamma-expand16-transform tests/pngvalid-gamma-sbit\
-   tests/pngvalid-gamma-threshold tests/pngvalid-gamma-transform\
-   tests/pngvalid-progressive-size\
-   tests/pngvalid-progressive-interlace-standard\
-   tests/pngvalid-transform\
-   tests/pngvalid-progressive-standard tests/pngvalid-standard\
-   tests/pngstest-1.8 tests/pngstest-1.8-alpha tests/pngstest-linear\
-   tests/pngstest-linear-alpha tests/pngstest-none tests/pngstest-none-alpha\
-   tests/pngstest-sRGB tests/pngstest-sRGB-alpha tests/pngunknown-IDAT\
-   tests/pngunknown-discard tests/pngunknown-if-safe tests/pngunknown-sAPI\
-   tests/pngunknown-sTER tests/pngunknown-save tests/pngunknown-vpAg\
-   tests/pngimage-quick tests/pngimage-full
-
-# man pages
-dist_man_MANS= libpng.3 libpngpf.3 png.5
-
-# generate the -config scripts if required
-binconfigs= libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
-EXTRA_SCRIPTS= libpng-config libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config
-bin_SCRIPTS= @binconfigs@
-
-# rules to build libpng, only build the old library on request
-lib_LTLIBRARIES=libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-# EXTRA_LTLIBRARIES= libpng.la
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = png.c pngerror.c\
-	pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c pngrutil.c\
-	pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c\
-	png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h pngusr.dfa
-
-if PNG_ARM_NEON
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += arm/arm_init.c\
-	arm/filter_neon.S arm/filter_neon_intrinsics.c
-endif
-
-nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
-
-libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS = -no-undefined -export-dynamic \
-	-version-number @PNGLIB_MAJOR@@PNGLIB_MINOR@:@PNGLIB_RELEASE@:0
-
-if HAVE_LD_VERSION_SCRIPT
-#   Versioned symbols and restricted exports
-if HAVE_SOLARIS_LD
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,-M -Wl,libpng.vers
-else
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -Wl,--version-script=libpng.vers
-endif
-
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.vers
-else
-#   Only restricted exports when possible
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_LDFLAGS += -export-symbols libpng.sym
-  libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_DEPENDENCIES = libpng.sym
-endif
-
-#distribute headers in /usr/include/libpng/*
-pkgincludedir= $(includedir)/$(PNGLIB_BASENAME)
-pkginclude_HEADERS= png.h pngconf.h
-nodist_pkginclude_HEADERS= pnglibconf.h
-
-# pkg-config stuff, note that libpng.pc is always required in order
-# to get the correct library
-pkgconfigdir = @pkgconfigdir@
-pkgconfig_DATA = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc
-
-# Extra source distribution files, '${srcdir}' is used below to stop build files
-# from those directories being included.  This only works if the configure is
-# not done in the source directory!
-EXTRA_DIST= \
-	ANNOUNCE CHANGES INSTALL LICENSE README TODO \
-	pngtest.png pngbar.png pngnow.png pngbar.jpg autogen.sh \
-	${srcdir}/contrib ${srcdir}/projects ${srcdir}/scripts \
-	$(TESTS) $(XFAIL_TESTS) tests/pngstest \
-	CMakeLists.txt example.c libpng-manual.txt
-
-SCRIPT_CLEANFILES=scripts/*.out scripts/*.chk
-
-CLEANFILES= *.tf? pngout.png libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.pc \
-	libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@-config libpng.vers libpng.sym \
-	check.new pnglibconf.h pngprefix.h symbols.new pngtest-log.txt \
-	pnglibconf.out pnglibconf.c pnglibconf.pre pnglibconf.dfn \
-	$(SCRIPT_CLEANFILES)
-
-MAINTAINERCLEANFILES = Makefile.in aclocal.m4 config.guess config.h.in \
-config.sub configure depcomp install-sh ltmain.sh missing
-
-# PNG_COPTS give extra options for the C compiler to be used on all compilation
-# steps (unless targe_CFLAGS is specified; that will take precedence over
-# AM_CFLAGS)
-PNG_COPTS = @PNG_COPTS@
-AM_CFLAGS = ${PNG_COPTS}
-
-# DFNCPP is normally just CPP - the C preprocessor - but on Solaris and maybe
-# other operating systems (NeXT?) the C preprocessor selected by configure
-# checks input tokens for validity - effectively it performs part of the ANSI-C
-# parsing - and therefore fails with the .df files.  configure.ac has special
-# checks for this and sets DFNCPP appropriately.
-DFNCPP = @DFNCPP@
-
-SUFFIXES = .chk .out
-
-$(PNGLIB_BASENAME).pc: libpng.pc
-	cp libpng.pc $@
-
-$(PNGLIB_BASENAME)-config: libpng-config
-	cp libpng-config $@
-
-scripts/sym.out scripts/vers.out: png.h pngconf.h pnglibconf.h
-scripts/prefix.out: png.h pngconf.h pnglibconf.out
-scripts/symbols.out: png.h pngconf.h $(srcdir)/scripts/pnglibconf.h.prebuilt
-scripts/intprefix.out: pnglibconf.h
-
-libpng.sym: scripts/sym.out
-	rm -f $@
-	cp $? $@
-libpng.vers: scripts/vers.out
-	rm -f $@
-	cp $? $@
-
-if DO_PNG_PREFIX
-# Rename functions in scripts/prefix.out with a PNG_PREFIX prefix.
-# Rename macros in scripts/macro.lst from PNG_PREFIXpng_ to PNG_ (the actual
-# implementation of the macro).
-pnglibconf.h: pnglibconf.out scripts/prefix.out scripts/macro.lst
-	rm -f $@
-	$(AWK) 's==0 && NR>1{print prev}\
-	   s==0{prev=$$0}\
-	   s==1{print "#define", $$1, "@PNG_PREFIX@" $$1}\
-	   s==2{print "#define @PNG_PREFIX@png_" $$1, "PNG_" $$1}\
-	   END{print prev}' s=0 pnglibconf.out s=1 scripts/prefix.out\
-	   s=2 ${srcdir}/scripts/macro.lst >pnglibconf.tf8
-	mv pnglibconf.tf8 $@
-
-pngprefix.h: scripts/intprefix.out
-	rm -f pngprefix.tf1
-	$(AWK) '{print "#define", $$1, "@PNG_PREFIX@" $$1}' $? >pngprefix.tf1
-	mv pngprefix.tf1 $@
-else
-pnglibconf.h: pnglibconf.out
-	rm -f $@
-	cp $? $@
-
-pngprefix.h: # is empty
-	:>$@
-endif
-
-$(srcdir)/scripts/pnglibconf.h.prebuilt:
-	@echo "Attempting to build $@" >&2
-	@echo "This is a machine generated file, but if you want to make" >&2
-	@echo "a new one simply make 'scripts/pnglibconf.out', copy that" >&2
-	@echo "AND set PNG_ZLIB_VERNUM to 0 (you MUST do this)" >&2
-	@exit 1
-
-# The following is necessary to ensure that the local pnglibconf.h is used, not
-# an installed one (this can happen immediately after on a clean system if
-# 'make test' is the first thing the user does.)  Only files which include
-# one of the png source files (typically png.h or pngpriv.h) need to be listed
-# here:
-pngtest.o: pnglibconf.h
-
-contrib/libtests/makepng.o: pnglibconf.h
-contrib/libtests/pngstest.o: pnglibconf.h
-contrib/libtests/pngunknown.o: pnglibconf.h
-contrib/libtests/pngimage.o: pnglibconf.h
-contrib/libtests/pngvalid.o: pnglibconf.h
-contrib/libtests/readpng.o: pnglibconf.h
-contrib/libtests/tarith.o: pnglibconf.h
-contrib/libtests/timepng.o: pnglibconf.h
-
-contrib/tools/makesRGB.o: pnglibconf.h
-contrib/tools/pngfix.o: pnglibconf.h
-contrib/tools/pngcp.o: pnglibconf.h
-
-# We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
-# be built with PNG_USE_READ_MACROS; this prevents the read macros from
-# interfering with the symbol file format.
-SYMBOL_CFLAGS = -DPNGLIB_LIBNAME='PNG@PNGLIB_MAJOR@@PNGLIB_MINOR@_0'\
-		-DPNGLIB_VERSION='@PNGLIB_VERSION@'\
-		-DSYMBOL_PREFIX='$(SYMBOL_PREFIX)'\
-		-DPNG_NO_USE_READ_MACROS -DPNG_BUILDING_SYMBOL_TABLE
-
-if DO_PNG_PREFIX
-SYMBOL_CFLAGS += -DPNG_PREFIX='@PNG_PREFIX@'
-endif
-
-.c.out:
-	rm -f $@ $*.tf[12]
-	test -d scripts || mkdir scripts || test -d scripts
-	$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES)\
-	    $(CPPFLAGS) $(SYMBOL_CFLAGS) $< > $*.tf1
-	$(AWK) -f "${srcdir}/scripts/dfn.awk" out="$*.tf2" $*.tf1 1>&2
-	rm -f $*.tf1
-	mv $*.tf2 $@
-
-# The .c file for pnglibconf.h is machine generated
-pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h pngusr.dfa $(DFA_XTRA)
-	rm -f $@ $*.tf[45]
-	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf4 version=search\
-	    ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
-	    ${srcdir}/pngusr.dfa $(DFA_XTRA) 1>&2
-	$(AWK) -f ${srcdir}/scripts/options.awk out=$*.tf5 $*.tf4 1>&2
-	rm $*.tf4
-	mv $*.tf5 $@
-
-# Symbol checks (.def and .out files should match)
-scripts/symbols.chk: scripts/checksym.awk scripts/symbols.def scripts/symbols.out
-
-.out.chk:
-	rm -f $@ $*.new
-	$(AWK) -f ${srcdir}/scripts/checksym.awk ${srcdir}/scripts/${*F}.def\
-	    of="$*.new" $< >&2
-	mv $*.new $@
-
-# used on demand to regenerate the standard header, CPPFLAGS should
-# be empty - no non-standard defines
-scripts/pnglibconf.c: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
-	rm -f $@ pnglibconf.tf[67]
-	test -z "$(CPPFLAGS)"
-	echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
-	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf6\
-	    logunsupported=1 version=search ${srcdir}/pngconf.h -\
-	    ${srcdir}/scripts/pnglibconf.dfa 1>&2
-	$(AWK) -f ${srcdir}/scripts/options.awk out=pnglibconf.tf7\
-	    pnglibconf.tf6 1>&2
-	rm pnglibconf.tf6
-	mv pnglibconf.tf7 $@
-
-$(libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_OBJECTS): png.h pngconf.h \
-	pnglibconf.h pngpriv.h pngdebug.h pnginfo.h pngstruct.h pngprefix.h
-
-test: check-am
-
-# Extra checks
-check: scripts/symbols.chk
-
-# Don't distribute the generated script files
-dist-hook:
-	cd '$(top_distdir)'; rm -f $(SCRIPT_CLEANFILES)
-
-# Make links between installed files with release-specific names and the generic
-# file names.  If this install rule is run the generic names will be deleted and
-# recreated - this has obvious issues for systems with multiple installations.
-
-install-header-links:
-	@set -ex; cd '$(DESTDIR)$(includedir)'; for f in $(HEADERS); do \
-	   rm -f "$$f"; $(LN_S) "$(PNGLIB_BASENAME)/$$f" "$$f"; done
-
-uninstall-header-links:
-	cd '$(DESTDIR)$(includedir)'; rm -f $(HEADERS)
-
-install-libpng-pc:
-	@set -ex; cd '$(DESTDIR)$(pkgconfigdir)'; rm -f libpng.pc; \
-	   $(LN_S) '$(PNGLIB_BASENAME).pc' libpng.pc
-
-uninstall-libpng-pc:
-	rm -f '$(DESTDIR)$(pkgconfigdir)/libpng.pc'
-
-# EXT_LIST is a list of the possibly library directory extensions, this exists
-# because we can't find a good way of discovering the file extensions that are
-# actually installed on a given system, so instead we check for every extension
-# we have seen.
-
-EXT_LIST = a dll.a so so.@PNGLIB_MAJOR@@PNGLIB_MINOR@.@PNGLIB_RELEASE@ la sl dylib
-
-install-library-links:
-	@set -x; cd '$(DESTDIR)$(libdir)';\
-	for ext in $(EXT_LIST); do\
-	   rm -f "libpng.$$ext";\
-           if test -f "$(PNGLIB_BASENAME).$$ext"; then\
-              $(LN_S) "$(PNGLIB_BASENAME).$$ext" "libpng.$$ext" || exit 1;\
-           fi;\
-	done
-
-uninstall-library-links:
-	@set -x; cd '$(DESTDIR)$(libdir)'; for ext in $(EXT_LIST); do\
-	   rm -f "libpng.$$ext"; done
-
-install-libpng-config:
-	@set -ex; cd '$(DESTDIR)$(bindir)'; rm -f libpng-config; \
-	   $(LN_S) '$(PNGLIB_BASENAME)-config' libpng-config
-
-uninstall-libpng-config:
-	rm -f '$(DESTDIR)$(bindir)/libpng-config'
-
-if DO_INSTALL_LINKS
-# If --enable-unversioned-links is specified the header and lib file links
-# will be automatically made on a 'make install':
-
-install-data-hook: install-header-links
-uninstall-hook: uninstall-header-links
-install-exec-hook: install-library-links
-uninstall-hook: uninstall-library-links
-endif
-
-if DO_INSTALL_LIBPNG_PC
-# Likewise, --install-pc causes libpng.pc to be constructed:
-
-install-data-hook: install-libpng-pc
-uninstall-hook: uninstall-libpng-pc
-endif
-
-if DO_INSTALL_LIBPNG_CONFIG
-# And --install-config:
-
-install-exec-hook: install-libpng-config
-uninstall-hook: uninstall-libpng-config
-endif
-
-# The following addition ensures that 'make all' always builds the test programs
-# too.  It used to, but some change either in libpng or configure stopped this
-# working.
-all-am: $(check_PROGRAMS)
diff --git a/README.fuchsia b/README.fuchsia
new file mode 100644
index 0000000..8e10a7b
--- /dev/null
+++ b/README.fuchsia
@@ -0,0 +1,24 @@
+Name: libpng
+URL: http://libpng.org/
+Version: 1.6.24
+Security Critical: yes
+License: libpng license
+License Android Compatible: yes
+Description:
+Updated to 1.6.24, stripped all unneeded files.
+
+- Turn on SSE optimizations for Intel platforms by running:
+  "patch -i contrib/intel/intel_sse.patch -p1"
+- Strip all unneeded files
+  mv contrib/intel contrib_intel_temp # Move contrib/intel temporarily.
+  rm -r projects scripts tests \
+        ANNOUNCE CHANGES INSTALL TODO autogen.sh configure.ac CMakeLists.txt Makefile.am \
+        *.in *.3 *.5 *.png *.jpg *.dfa libpng-manual.txt \
+        contrib/*
+  mv contrib_intel_temp contrib/intel # Move contrib/intel back.
+
+- Use custom configuration file pnglibconf.h, which turns off all features that
+  are not in use.
+- Use custom prefix file pngprefix.h, which avoids namespace conflicts with
+  pdfium's copy of libpng.
+- Configures custom png chunk user limits (crbug.com/117369) in pnglibconf.h.
diff --git a/TODO b/TODO
deleted file mode 100644
index 0b3b651..0000000
--- a/TODO
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
-TODO - list of things to do for libpng:
-
-Final bug fixes.
-Better C++ wrapper/full C++ implementation?
-Fix problem with C++ and EXTERN "C".
-cHRM transformation.
-Remove setjmp/longjmp usage in favor of returning error codes.
-Palette creation.
-Add "grayscale->palette" transformation and "palette->grayscale" detection.
-Improved dithering.
-Multi-lingual error and warning message support.
-Complete sRGB transformation (presently it simply uses gamma=0.45455).
-Man pages for function calls.
-Better documentation.
-Better filter selection
-   (counting huffman bits/precompression?  filter inertia?  filter costs?).
-Histogram creation.
-Text conversion between different code pages (Latin-1 -> Mac and DOS).
-Avoid building gamma tables whenever possible.
-Use greater precision when changing to linear gamma for compositing against
-  background and doing rgb-to-gray transformation.
-Investigate pre-incremented loop counters and other loop constructions.
-Add interpolated method of handling interlacing.
-Switch to the simpler zlib (zlib/libpng) license if legally possible.
-Extend pngvalid.c to validate more of the libpng transformations.
-
-*/
diff --git a/autogen.sh b/autogen.sh
deleted file mode 100755
index 9160717..0000000
--- a/autogen.sh
+++ /dev/null
@@ -1,225 +0,0 @@
-#! /bin/sh
-#
-# Run 'autoreconf' to build 'configure', 'Makefile.in' and other configure
-# control files.
-#
-# The first time this is run on a GIT checkout the only files that exist are
-# configure.ac and Makefile.am; all of the autotools support scripts are
-# missing.  They are instantiated with autoreconf --force --install.
-#
-# For regular ("tarball") distributions all the files should exist.  We do not
-# want them to be updated *under any circumstances*.  It should never be
-# necessary to run autogen.sh because ./configure --enable-maintainer-mode says
-# what to do if Makefile.am or configure.ac are changed.
-#
-# It is *probably* OK to update the files on a GIT checkout, because they have
-# come from the local tools, but leave that to the user who is assumed to know
-# whether it is ok or required.
-#
-# This script is intended to work without arguments, there are, however, hidden
-# arguments (a) for use while testing the script and (b) to fix up systems that
-# have been broken.  If (b) is required the script prompts for the correct
-# options.  For this reason the options are *NOT* documented in the help; this
-# is deliberate; UTSL.
-#
-clean=
-maintainer=
-while test $# -gt 0
-do
-   case "$1" in
-      --maintainer)
-         maintainer=1;;
-
-      --clean)
-         clean=1;;
-
-      *)
-         exec >&2
-         echo "$0: usage: ./autogen.sh"
-         if test -d .git
-         then
-            echo "  ./autogen.sh generates the configure script and"
-            echo "  Makefile.in, or refreshes them after changes to Makefile.am"
-            echo "  or configure.ac.  You may prefer to just run autoreconf."
-         elif test -z "$maintainer"
-         then
-            echo "  DO NOT RUN THIS SCRIPT."
-            echo "  If you need to change Makefile.am or configure.ac then you"
-            echo "  also need to run ./configure --enable-maintainer-mode and"
-            echo "  use the appropriate autotools, *NOT* this script, to update"
-            echo "  everything, please check the documentation of autoreconf."
-            echo "  WARNING: libpng is intentionally generated with a known,"
-            echo "  fixed, set of autotools.  It is known *NOT* to work with"
-            echo "  the collection of autotools distributed on highly reputable"
-            echo "  operating systems."
-            echo "  Remember: autotools is GNU software, you are expected to"
-            echo "  pay for support."
-         else
-            echo "  You have run autogen.sh with --maintainer enabled and you"
-            echo "  are not using a GIT distribution, then you have given an"
-            echo "  unrecognized argument.  This is not good. --maintainer"
-            echo "  switches off any assumptions that you might not know what"
-            echo "  you are doing."
-         fi
-         exit 1;;
-   esac
-
-   shift
-done
-#
-# First check for a set of the autotools files; if absent then this is assumed
-# to be a GIT version and the local autotools must be used.  If present this
-# is a tarball distribution and the script should not be used.  If partially
-# present bad things are happening.
-#
-# The autotools generated files:
-libpng_autotools_files="Makefile.in aclocal.m4 config.guess config.h.in
-   config.sub configure depcomp install-sh ltmain.sh missing\
-   test-driver"
-#
-# Files generated by versions of configue >2.68 or automake >1.13 (i.e. later
-# versions than those required by configure.ac):
-libpng_autotools_extra="compile config.h.in~"
-#
-# These are separate because 'maintainer-clean' does not remove them.
-libpng_libtool_files="scripts/libtool.m4 scripts/ltoptions.m4\
-   scripts/ltsugar.m4 scripts/ltversion.m4 scripts/lt~obsolete.m4"
-
-libpng_autotools_dirs="autom4te.cache" # not required
-#
-# The configure generated files:
-libpng_configure_files="Makefile config.h config.log config.status\
-   libpng-config libpng.pc libtool stamp-h1"
-
-libpng_configure_dirs=".deps"
-#
-# We must remove the configure generated files as well as the autotools
-# generated files if autotools are regenerated because otherwise if configure
-# has been run without "--enable-maintainer-mode" make can do a partial update
-# of Makefile.  These functions do the two bits of cleaning.
-clean_autotools(){
-   rm -rf $libpng_autotools_files $libpng_libtool_files $libpng_autotools_dirs
-   rm -rf $libpng_autotools_extra
-}
-
-clean_configure(){
-   rm -rf $libpng_configure_files $libpng_configure_dirs
-}
-#
-# Clean: remove everything (this is to help with testing)
-if test -n "$clean"
-then
-   clean_configure
-   if test -n "$maintainer"
-   then
-      clean_autotools
-   fi
-
-   exit 0
-fi
-#
-# Validate the distribution.
-libpng_autotools_file_found=
-libpng_autotools_file_missing=
-for file in $libpng_autotools_files
-do
-   if test -f  "$file"
-   then
-      libpng_autotools_file_found=1
-   else
-      libpng_autotools_file_missing=1
-   fi
-done
-#
-# Presence of one of these does not *invalidate* missing, but absence
-# invalidates found.
-for file in $libpng_libtool_files
-do
-   if test ! -f "$file"
-   then
-      libpng_autotools_file_missing=1
-   fi
-done
-#
-# The cache directory doesn't matter - it will be regenerated and does not exist
-# anyway in a tarball.
-#
-# Either everything is missing or everything is there, the --maintainer option
-# just changes this so that the mode is set to generate all the files.
-mode=
-if test -z "$libpng_autotools_file_found" -o -n "$maintainer"
-then
-   mode="autoreconf"
-else
-   if test -n "$libpng_autotools_file_missing"
-   then
-      mode="broken"
-   else
-      mode="configure"
-   fi
-fi
-#
-# So:
-case "$mode" in
-   autoreconf)
-      # Clean in case configure files exist
-      clean_configure
-      clean_autotools
-      # Everything must be initialized, so use --force
-      if autoreconf --warnings=all --force --install
-      then
-         missing=
-         for file in $libpng_autotools_files
-         do
-            test -f "$file" || missing=1
-         done
-         # ignore the cache directory
-         test -z "$missing" || {
-            exec >&2
-            echo "autoreconf was run, but did not produce all the expected"
-            echo "files.  It is likely that your autotools installation is"
-            echo "not compatible with that expected by libpng."
-            exit 1
-         }
-      else
-         exec >&2
-         echo "autoreconf failed: your version of autotools is incompatible"
-         echo "with this libpng version.  Please use a distributed archive"
-         echo "(which includes the autotools generated files) and run configure"
-         echo "instead."
-         exit 1
-      fi;;
-
-   configure)
-      if test -d .git
-      then
-         exec >&2
-         echo "ERROR: running autoreconf on an initialized sytem"
-         echo "  This is not necessary; it is only necessary to remake the"
-         echo "  autotools generated files if Makefile.am or configure.ac"
-         echo "  change and make does the right thing with:"
-         echo
-         echo "     ./configure --enable-maintainer-mode."
-         echo
-         echo "  You can run autoreconf yourself if you don't like maintainer"
-         echo "  mode and you can also just run autoreconf -f -i to initialize"
-         echo "  everything in the first place; this script is only for"
-         echo "  compatibility with prior releases."
-         exit 1
-      else
-         exec >&2
-         echo "autogen.sh is intended only to generate 'configure' on systems"
-         echo "that do not have it.  You have a complete 'configure', if you"
-         echo "need to change Makefile.am or configure.ac you also need to"
-         echo "run configure with the --enable-maintainer-mode option."
-         exit 1
-      fi;;
-
-   broken)
-      exec >&2
-      echo "Your system has a partial set of autotools generated files."
-      echo "autogen.sh is unable to proceed.  The full set of files is"
-      echo "contained in the libpng 'tar' distribution archive and you do"
-      echo "not need to run autogen.sh if you use it."
-      exit 1;;
-esac
diff --git a/configure.ac b/configure.ac
deleted file mode 100644
index 3a3d208..0000000
--- a/configure.ac
+++ /dev/null
@@ -1,356 +0,0 @@
-# configure.ac
-
-# Copyright (c) 2004-2015 Glenn Randers-Pehrson
-# Last changed in libpng 1.6.22 [May 26, 2016]
-
-# This code is released under the libpng license.
-# For conditions of distribution and use, see the disclaimer
-# and license in png.h
-
-dnl Process this file with autoconf to produce a configure script.
-dnl
-dnl Minor upgrades (compatible ABI): increment the package version
-dnl (third field in two places below) and set the PNGLIB_RELEASE
-dnl variable.
-dnl
-dnl Major upgrades (incompatible ABI): increment the package major
-dnl version (second field, or first if desired), set the minor
-dnl to 0, set PNGLIB_MAJOR below *and* follow the instructions in
-dnl Makefile.am to upgrade the package name.
-
-dnl This is here to prevent earlier autoconf from being used, it
-dnl should not be necessary to regenerate configure if the time
-dnl stamps are correct
-AC_PREREQ([2.68])
-
-dnl Version number stuff here:
-
-AC_INIT([libpng],[1.6.24],[png-mng-implement@lists.sourceforge.net])
-AC_CONFIG_MACRO_DIR([scripts])
-
-# libpng does not follow GNU file name conventions (hence 'foreign')
-# color-tests requires automake 1.11 or later
-# silent-rules requires automake 1.11 or later
-# dist-xz requires automake 1.11 or later
-# 1.12.2 fixes a security issue in 1.11.2 and 1.12.1
-# 1.13 is required for parallel tests
-AM_INIT_AUTOMAKE([1.13 foreign dist-xz color-tests silent-rules subdir-objects])
-# The following line causes --disable-maintainer-mode to be the default to
-# configure. This is necessary because libpng distributions cannot rely on the
-# time stamps of the autotools generated files being correct
-AM_MAINTAINER_MODE
-
-dnl configure.ac and Makefile.am expect automake 1.11.2 or a compatible later
-dnl version; aclocal.m4 will generate a failure if you use a prior version of
-dnl automake, so the following is not necessary (and is not defined anyway):
-dnl AM_PREREQ([1.11.2])
-dnl stop configure from automagically running automake
-
-PNGLIB_VERSION=1.6.24
-PNGLIB_MAJOR=1
-PNGLIB_MINOR=6
-PNGLIB_RELEASE=24
-
-dnl End of version number stuff
-
-AC_CONFIG_SRCDIR([pngget.c])
-AC_CONFIG_HEADERS([config.h])
-
-# Checks for programs.
-AC_LANG([C])
-AC_PROG_CC
-AM_PROG_AS
-LT_PATH_LD
-AC_PROG_CPP
-AC_PROG_AWK
-AC_PROG_INSTALL
-AC_PROG_LN_S
-AC_PROG_MAKE_SET
-
-dnl libtool/libtoolize; version 2.4.2 is the tested version. This or any
-dnl compatible later version may be used
-LT_INIT([win32-dll])
-LT_PREREQ([2.4.2])
-
-# Some awks crash when confronted with pnglibconf.dfa, do a test run now
-# to make sure this doesn't happen
-AC_MSG_CHECKING([that AWK works])
-if ${AWK} -f ${srcdir}/scripts/options.awk out="/dev/null" version=search\
-   ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
-   ${srcdir}/pngusr.dfa 1>&2
-then
-   AC_MSG_RESULT([ok])
-else
-   AC_MSG_FAILURE([failed], 1)
-fi
-
-# This is a remnant of the old cc -E validation, where it may have been
-# necessary to use a different preprocessor for .dfn files
-DFNCPP="$CPP"
-AC_SUBST(DFNCPP)
-
-# -Werror cannot be passed to GCC in CFLAGS because configure will fail (it
-# checks the compiler with a program that generates a warning), add the
-# following option to deal with this
-AC_ARG_VAR(PNG_COPTS,
-   [additional flags for the C compiler, use this for options that would]
-   [cause configure itself to fail])
-AC_ARG_ENABLE(werror,
-   AS_HELP_STRING([[[--enable-werror[=OPT]]]],
-      [Pass -Werror or the given argument to the compiler if it is supported]),
-   [test "$enable_werror" = "yes" && enable_werror="-Werror"
-    if test "$enable_werror" != "no"; then
-      sav_CFLAGS="$CFLAGS"
-      CFLAGS="$enable_werror $CFLAGS"
-      AC_MSG_CHECKING([if the compiler allows $enable_werror])
-      AC_COMPILE_IFELSE(
-         [AC_LANG_SOURCE([
-            [int main(int argc, char **argv){]
-            [return argv[argc-1][0];]
-            [}]])],
-         AC_MSG_RESULT(yes)
-         PNG_COPTS="$PNG_COPTS $enable_werror",
-         AC_MSG_RESULT(no))
-      CFLAGS="$sav_CFLAGS"
-    fi],)
-
-# For GCC 5 the default mode for C is -std=gnu11 instead of -std=gnu89
-# In pngpriv.h we request just the POSIX 1003.1 and C89 APIs by defining _POSIX_SOURCE to 1
-# This is incompatible with the new default mode, so we test for that and force the 
-# "-std=c89" compiler option:
-AC_MSG_CHECKING([if we need to force back C standard to C89])
-AC_COMPILE_IFELSE(
-   [AC_LANG_PROGRAM([
-      [#define _POSIX_SOURCE 1]
-      [#include <stdio.h>]
-   ])],
-   AC_MSG_RESULT(no),[
-      if test "x$GCC" != "xyes"; then
-         AC_MSG_ERROR(
-            [Forcing back to C89 is required but the flags are only known for GCC])
-      fi
-   AC_MSG_RESULT(yes)
-   CFLAGS="$CFLAGS -std=c89"
-])
-
-# Checks for header files.
-AC_HEADER_STDC
-
-# Checks for typedefs, structures, and compiler characteristics.
-AC_C_CONST
-AC_TYPE_SIZE_T
-AC_STRUCT_TM
-AC_C_RESTRICT
-
-# Checks for library functions.
-AC_FUNC_STRTOD
-AC_CHECK_FUNCS([memset], , AC_MSG_ERROR(memset not found in libc))
-AC_CHECK_FUNCS([pow], , AC_CHECK_LIB(m, pow, , AC_MSG_ERROR(cannot find pow)) )
-
-# Some later POSIX 1003.1 functions are required for test programs, failure here
-# is soft (the corresponding test program is not built).
-AC_CHECK_FUNC([clock_gettime],,[AC_MSG_WARN([not building timepng])])
-AM_CONDITIONAL([HAVE_CLOCK_GETTIME], [test "$ac_cv_func_clock_gettime" = "yes"])
-
-AC_ARG_WITH(zlib-prefix,
-   AS_HELP_STRING([[[--with-zlib-prefix]]],
-      [prefix that may have been used in installed zlib]),
-      [ZPREFIX=${withval}],
-      [ZPREFIX='z_'])
-AC_CHECK_LIB(z, zlibVersion, ,
-    AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, , AC_MSG_ERROR(zlib not installed)))
-
-# The following is for pngvalid, to ensure it catches FP errors even on
-# platforms that don't enable FP exceptions, the function appears in the math
-# library (typically), it's not an error if it is not found.
-AC_CHECK_LIB([m], [feenableexcept])
-AC_CHECK_FUNCS([feenableexcept])
-
-AC_MSG_CHECKING([if using Solaris linker])
-SLD=`$LD --version 2>&1 | grep Solaris`
-if test "$SLD"; then
-    have_solaris_ld=yes
-    AC_MSG_RESULT(yes)
-else
-    have_solaris_ld=no
-    AC_MSG_RESULT(no)
-fi
-AM_CONDITIONAL(HAVE_SOLARIS_LD, test "$have_solaris_ld" = "yes")
-
-AC_MSG_CHECKING([if libraries can be versioned])
-# Special case for PE/COFF platforms: ld reports
-# support for version-script, but doesn't actually
-# DO anything with it.
-case $host in
-*cygwin* | *mingw32* | *interix* )
-    have_ld_version_script=no
-    AC_MSG_RESULT(no)
-;;
-* )
-
-if test "$have_solaris_ld" = "yes"; then
-    GLD=`$LD --help < /dev/null 2>&1 | grep 'M mapfile'`
-else
-    GLD=`$LD --help < /dev/null 2>/dev/null | grep version-script`
-fi
-
-if test "$GLD"; then
-    have_ld_version_script=yes
-    AC_MSG_RESULT(yes)
-else
-    have_ld_version_script=no
-    AC_MSG_RESULT(no)
-    AC_MSG_WARN(*** You have not enabled versioned symbols.)
-fi
-;;
-esac
-
-AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
-
-if test "$have_ld_version_script" = "yes"; then
-    AC_MSG_CHECKING([for symbol prefix])
-    SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
-                  | ${CPP-${CC-gcc} -E} - 2>&1 \
-                  | ${EGREP-grep} "^PREFIX=" \
-                  | ${SED-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
-    AC_SUBST(SYMBOL_PREFIX)
-    AC_MSG_RESULT($SYMBOL_PREFIX)
-fi
-
-# Substitutions for .in files
-AC_SUBST(PNGLIB_VERSION)
-AC_SUBST(PNGLIB_MAJOR)
-AC_SUBST(PNGLIB_MINOR)
-AC_SUBST(PNGLIB_RELEASE)
-
-# Additional arguments (and substitutions)
-# Allow the pkg-config directory to be set
-AC_ARG_WITH(pkgconfigdir,
-   AS_HELP_STRING([[[--with-pkgconfigdir]]],
-      [Use the specified pkgconfig dir (default is libdir/pkgconfig)]),
-   [pkgconfigdir=${withval}],
-   [pkgconfigdir='${libdir}/pkgconfig'])
-
-AC_SUBST([pkgconfigdir])
-AC_MSG_NOTICE([[pkgconfig directory is ${pkgconfigdir}]])
-
-# Make the *-config binary config scripts optional
-AC_ARG_WITH(binconfigs,
-   AS_HELP_STRING([[[--with-binconfigs]]],
-      [Generate shell libpng-config scripts as well as pkg-config data]
-      [@<:@default=yes@:>@]),
-   [if test "${withval}" = no; then
-      binconfigs=
-      AC_MSG_NOTICE([[libpng-config scripts will not be built]])
-    else
-      binconfigs='${binconfigs}'
-    fi],
-   [binconfigs='${binconfigs}'])
-AC_SUBST([binconfigs])
-
-# Support for prefixes to the API function names; this will generate defines
-# at the start of the build to rename exported library functions
-AC_ARG_WITH(libpng-prefix,
-   AS_HELP_STRING([[[--with-libpng-prefix]]],
-      [prefix libpng exported function (API) names with the given value]),
-   [if test "${withval:-no}" != "no"; then
-      AC_SUBST([PNG_PREFIX], [${withval}])
-    fi])
-AM_CONDITIONAL([DO_PNG_PREFIX], [test "${with_libpng_prefix:-no}" != "no"])
-
-# Control over what links are made for installed files.  Versioned files are
-# always installed, when the following options are turned on corresponding
-# unversioned links are also created (normally as symbolic links):
-AC_ARG_ENABLE([unversioned-links],
-   AS_HELP_STRING([[[--enable-unversioned-links]]],
-      [Installed libpng header files are placed in a versioned subdirectory]
-      [and installed libpng library (including DLL) files are versioned.]
-      [If this option is enabled unversioned links will be created pointing to]
-      [the corresponding installed files.  If you use libpng.pc or]
-      [libpng-config for all builds you do not need these links, but if you]
-      [compile programs directly they will typically #include <png.h> and]
-      [link with -lpng; in that case you need the links.]
-      [The links can be installed manually using 'make install-header-links']
-      [and 'make install-library-links' and can be removed using the]
-      [corresponding uninstall- targets.  If you do enable this option every]
-      [libpng 'make install' will recreate the links to point to the just]
-      [installed version of libpng.  The default is to create the links;]
-      [use --disable-unversioned-links to change this]))
-
-# The AM_CONDITIONAL test is written so that the default is enabled;
-# --disable-unversioned-links must be given to turn the option off.
-AM_CONDITIONAL([DO_INSTALL_LINKS],[test "$enable_unversioned_links" != "no"])
-
-AC_ARG_ENABLE([unversioned-libpng-pc],
-   AS_HELP_STRING([[[--enable-unversioned-libpng-pc]]],
-      [Install the configuration file 'libpng.pc' as a link to the versioned]
-      [version.  This is done by default - use --disable-unversioned-libpng-pc]
-      [to change this.]))
-AM_CONDITIONAL([DO_INSTALL_LIBPNG_PC],
-   [test "$enable_unversioned_libpng_pc" != "no"])
-
-AC_ARG_ENABLE([unversioned-libpng-config],
-   AS_HELP_STRING([[[--enable-unversioned-libpng-config]]],
-      [Install the configuration file 'libpng-config' as a link to the]
-      [versioned version.  This is done by default - use]
-      [--disable-unversioned-libpng-config to change this.]))
-AM_CONDITIONAL([DO_INSTALL_LIBPNG_CONFIG],
-   [test "$enable_unversioned_libpng_config" != "no"])
-
-# HOST SPECIFIC OPTIONS
-# =====================
-#
-# ARM
-# ===
-#
-# ARM NEON (SIMD) support.
-
-AC_ARG_ENABLE([arm-neon],
-   AS_HELP_STRING([[[--enable-arm-neon]]],
-      [Enable ARM NEON optimizations: =no/off, check, api, yes/on:]
-      [no/off: disable the optimizations; check: use internal checking code]
-      [(deprecated and poorly supported); api: disable by default, enable by]
-      [a call to png_set_option; yes/on: turn on unconditionally.]
-      [If not specified: determined by the compiler.]),
-   [case "$enableval" in
-      no|off)
-         # disable the default enabling on __ARM_NEON__ systems:
-         AC_DEFINE([PNG_ARM_NEON_OPT], [0],
-                   [Disable ARM Neon optimizations])
-         # Prevent inclusion of the assembler files below:
-         enable_arm_neon=no;;
-      check)
-         AC_DEFINE([PNG_ARM_NEON_CHECK_SUPPORTED], [],
-                   [Check for ARM Neon support at run-time]);;
-      api)
-         AC_DEFINE([PNG_ARM_NEON_API_SUPPORTED], [],
-                   [Turn on ARM Neon optimizations at run-time]);;
-      yes|on)
-         AC_DEFINE([PNG_ARM_NEON_OPT], [2],
-                   [Enable ARM Neon optimizations])
-         AC_MSG_WARN([--enable-arm-neon: please specify 'check' or 'api', if]
-            [you want the optimizations unconditionally pass -mfpu=neon]
-            [to the compiler.]);;
-      *)
-         AC_MSG_ERROR([--enable-arm-neon=${enable_arm_neon}: invalid value])
-   esac])
-
-# Add ARM specific files to all builds where the host_cpu is arm ('arm*') or
-# where ARM optimizations were explicitly requested (this allows a fallback if a
-# future host CPU does not match 'arm*')
-
-AM_CONDITIONAL([PNG_ARM_NEON],
-   [test "$enable_arm_neon" != 'no' &&
-    case "$host_cpu" in
-      arm*|aarch64*) :;;
-      *)    test "$enable_arm_neon" != '';;
-    esac])
-
-AC_MSG_NOTICE([[Extra options for compiler: $PNG_COPTS]])
-
-# Config files, substituting as above
-AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
-AC_CONFIG_FILES([libpng-config:libpng-config.in],
-   [chmod +x libpng-config])
-
-AC_OUTPUT
diff --git a/contrib/README.txt b/contrib/README.txt
deleted file mode 100644
index 97963c6..0000000
--- a/contrib/README.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-
-This "contrib" directory contains contributions which are not necessarily under
-the libpng license, although all are open source.  They are not part of
-libpng proper and are not used for building the library, although some are used
-for testing the library via "make check".
diff --git a/contrib/arm-neon/README b/contrib/arm-neon/README
deleted file mode 100644
index b4248cf..0000000
--- a/contrib/arm-neon/README
+++ /dev/null
@@ -1,83 +0,0 @@
-OPERATING SYSTEM SPECIFIC ARM NEON DETECTION
---------------------------------------------
-
-Detection of the ability to execute ARM NEON on an ARM processor requires
-operating system support.  (The information is not available in user mode.)
-
-HOW TO USE THIS
----------------
-
-This directory contains C code fragments that can be included in arm/arm_init.c
-by setting the macro PNG_ARM_NEON_FILE to the file name in "" or <> at build
-time.  This setting is not recorded in pnglibconf.h and can be changed simply by
-rebuilding arm/arm_init.o with the required macro definition.
-
-For any of this code to be used the ARM NEON code must be enabled and run time
-checks must be supported.  I.e.:
-
-#if PNG_ARM_NEON_OPT > 0
-#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
-
-This is done in a 'configure' build by passing configure the argument:
-
-   --enable-arm-neon=check
-
-Apart from the basic Linux implementation in contrib/arm-neon/linux.c this code
-is unsupported.  That means that it is not even compiled on a regular basis and
-may be broken in any given minor release.
-
-FILE FORMAT
------------
-
-Each file documents its testing status as of the last time it was tested (which
-may have been a long time ago):
-
-STATUS: one of:
-   SUPPORTED: This indicates that the file is included in the regularly
-         performed test builds and bugs are fixed when discovered.
-   COMPILED: This indicates that the code did compile at least once.  See the
-         more detailed description for the extent to which the result was
-         successful.
-   TESTED: This means the code was fully compiled into the libpng test programs
-         and these were run at least once.
-
-BUG REPORTS: an email address to which to send reports of problems
-
-The file is a fragment of C code. It should not define any 'extern' symbols;
-everything should be static.  It must define the function:
-
-static int png_have_neon(png_structp png_ptr);
-
-That function must return 1 if ARM NEON instructions are supported, 0 if not.
-It must not execute png_error unless it detects a bug.  A png_error will prevent
-the reading of the PNG and in the future, writing too.
-
-BUG REPORTS
------------
-
-If you mail a bug report for any file that is not SUPPORTED there may only be
-limited response.  Consider fixing it and sending a patch to fix the problem -
-this is more likely to result in action.
-
-CONTRIBUTIONS
--------------
-
-You may send contributions of new implementations to
-png-mng-implement@sourceforge.net.  Please write code in strict C90 C where
-possible.  Obviously OS dependencies are to be expected.  If you submit code you
-must have the authors permission and it must have a license that is acceptable
-to the current maintainer; in particular that license must permit modification
-and redistribution.
-
-Please try to make the contribution a single file and give the file a clear and
-unambiguous name that identifies the target OS.  If multiple files really are
-required put them all in a sub-directory.
-
-You must also be prepared to handle bug reports from users of the code, either
-by joining the png-mng-implement mailing list or by providing an email for the
-"BUG REPORTS" entry or both.  Please make sure that the header of the file
-contains the STATUS and BUG REPORTS fields as above.
-
-Please list the OS requirements as precisely as possible.  Ideally you should
-also list the environment in which the code has been tested and certainly list
-any environments where you suspect it might not work.
diff --git a/contrib/arm-neon/android-ndk.c b/contrib/arm-neon/android-ndk.c
deleted file mode 100644
index 7240123..0000000
--- a/contrib/arm-neon/android-ndk.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/* contrib/arm-neon/android-ndk.c
- *
- * Copyright (c) 2014 Glenn Randers-Pehrson
- * Written by John Bowler, 2014.
- * Last changed in libpng 1.6.10 [March 6, 2014]
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * SEE contrib/arm-neon/README before reporting bugs
- *
- * STATUS: COMPILED, UNTESTED
- * BUG REPORTS: png-mng-implement@sourceforge.net
- *
- * png_have_neon implemented for the Android NDK, see:
- *
- * Documentation:
- *    http://www.kandroid.org/ndk/docs/CPU-ARM-NEON.html
- *    http://code.google.com/p/android/issues/detail?id=49065
- *
- * NOTE: this requires that libpng is built against the Android NDK and linked
- * with an implementation of the Android ARM 'cpu-features' library.  The code
- * has been compiled only, not linked: no version of the library has been found,
- * only the header files exist in the NDK.
- */
-#include <cpu-features.h>
-
-static int
-png_have_neon(png_structp png_ptr)
-{
-   /* This is a whole lot easier than the linux code, however it is probably
-    * implemented as below, therefore it is better to cache the result (these
-    * function calls may be slow!)
-    */
-   PNG_UNUSED(png_ptr)
-   return android_getCpuFamily() == ANDROID_CPU_FAMILY_ARM &&
-      (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0;
-}
diff --git a/contrib/arm-neon/linux-auxv.c b/contrib/arm-neon/linux-auxv.c
deleted file mode 100644
index 4d26bd3..0000000
--- a/contrib/arm-neon/linux-auxv.c
+++ /dev/null
@@ -1,120 +0,0 @@
-/* contrib/arm-neon/linux-auxv.c
- *
- * Copyright (c) 2014 Glenn Randers-Pehrson
- * Written by Mans Rullgard, 2011.
- * Last changed in libpng 1.6.10 [March 6, 2014]
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * SEE contrib/arm-neon/README before reporting bugs
- *
- * STATUS: COMPILED, TESTED
- * BUG REPORTS: png-mng-implement@sourceforge.net
- *
- * png_have_neon implemented for Linux versions which allow access to
- * /proc/self/auxv.  This is probably faster, cleaner and safer than the code to
- * read /proc/cpuinfo in contrib/arm-neon/linux, however it is yet another piece
- * of potentially untested code and has more complex dependencies than the code
- * to read cpuinfo.
- *
- * This generic __linux__ implementation requires reading /proc/self/auxv and
- * looking at each element for one that records NEON capabilities.
- */
-#include <unistd.h> /* for POSIX 1003.1 */
-#include <errno.h>  /* for EINTR */
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <elf.h>
-#include <asm/hwcap.h>
-
-/* A read call may be interrupted, in which case it returns -1 and sets errno to
- * EINTR if nothing was done, otherwise (if something was done) a partial read
- * may result.
- */
-static size_t
-safe_read(png_structp png_ptr, int fd, void *buffer_in, size_t nbytes)
-{
-   size_t ntotal = 0;
-   char *buffer = png_voidcast(char*, buffer_in);
-
-   while (nbytes > 0)
-   {
-      unsigned int nread;
-      int iread;
-
-      /* Passing nread > INT_MAX to read is implementation defined in POSIX
-       * 1003.1, therefore despite the unsigned argument portable code must
-       * limit the value to INT_MAX!
-       */
-      if (nbytes > INT_MAX)
-         nread = INT_MAX;
-
-      else
-         nread = (unsigned int)/*SAFE*/nbytes;
-
-      iread = read(fd, buffer, nread);
-
-      if (iread == -1)
-      {
-         /* This is the devil in the details, a read can terminate early with 0
-          * bytes read because of EINTR, yet it still returns -1 otherwise end
-          * of file cannot be distinguished.
-          */
-         if (errno != EINTR)
-         {
-            png_warning(png_ptr, "/proc read failed");
-            return 0; /* I.e., a permanent failure */
-         }
-      }
-
-      else if (iread < 0)
-      {
-         /* Not a valid 'read' result: */
-         png_warning(png_ptr, "OS /proc read bug");
-         return 0;
-      }
-
-      else if (iread > 0)
-      {
-         /* Continue reading until a permanent failure, or EOF */
-         buffer += iread;
-         nbytes -= (unsigned int)/*SAFE*/iread;
-         ntotal += (unsigned int)/*SAFE*/iread;
-      }
-
-      else
-         return ntotal;
-   }
-
-   return ntotal; /* nbytes == 0 */
-}
-
-static int
-png_have_neon(png_structp png_ptr)
-{
-   int fd = open("/proc/self/auxv", O_RDONLY);
-   Elf32_auxv_t aux;
-
-   /* Failsafe: failure to open means no NEON */
-   if (fd == -1)
-   {
-      png_warning(png_ptr, "/proc/self/auxv open failed");
-      return 0;
-   }
-
-   while (safe_read(png_ptr, fd, &aux, sizeof aux) == sizeof aux)
-   {
-      if (aux.a_type == AT_HWCAP && (aux.a_un.a_val & HWCAP_NEON) != 0)
-      {
-         close(fd);
-         return 1;
-      }
-   }
-
-   close(fd);
-   return 0;
-}
diff --git a/contrib/arm-neon/linux.c b/contrib/arm-neon/linux.c
deleted file mode 100644
index 94f9bb1..0000000
--- a/contrib/arm-neon/linux.c
+++ /dev/null
@@ -1,161 +0,0 @@
-/* contrib/arm-neon/linux.c
- *
- * Copyright (c) 2014 Glenn Randers-Pehrson
- * Written by John Bowler, 2014.
- * Last changed in libpng 1.6.16 [December 22, 2014]
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * SEE contrib/arm-neon/README before reporting bugs
- *
- * STATUS: SUPPORTED
- * BUG REPORTS: png-mng-implement@sourceforge.net
- *
- * png_have_neon implemented for Linux by reading the widely available
- * pseudo-file /proc/cpuinfo.
- *
- * This code is strict ANSI-C and is probably moderately portable; it does
- * however use <stdio.h> and it assumes that /proc/cpuinfo is never localized.
- */
-#include <stdio.h>
-
-static int
-png_have_neon(png_structp png_ptr)
-{
-   FILE *f = fopen("/proc/cpuinfo", "rb");
-
-   if (f != NULL)
-   {
-      /* This is a simple state machine which reads the input byte-by-byte until
-       * it gets a match on the 'neon' feature or reaches the end of the stream.
-       */
-      static const char ch_feature[] = { 70, 69, 65, 84, 85, 82, 69, 83 };
-      static const char ch_neon[] = { 78, 69, 79, 78 };
-
-      enum
-      {
-         StartLine, Feature, Colon, StartTag, Neon, HaveNeon, SkipTag, SkipLine
-      }  state;
-      int counter;
-
-      for (state=StartLine, counter=0;;)
-      {
-         int ch = fgetc(f);
-
-         if (ch == EOF)
-         {
-            /* EOF means error or end-of-file, return false; neon at EOF is
-             * assumed to be a mistake.
-             */
-            fclose(f);
-            return 0;
-         }
-
-         switch (state)
-         {
-            case StartLine:
-               /* Match spaces at the start of line */
-               if (ch <= 32) /* skip control characters and space */
-                  break;
-
-               counter=0;
-               state = Feature;
-               /* FALL THROUGH */
-
-            case Feature:
-               /* Match 'FEATURE', ASCII case insensitive. */
-               if ((ch & ~0x20) == ch_feature[counter])
-               {
-                  if (++counter == (sizeof ch_feature))
-                     state = Colon;
-                  break;
-               }
-
-               /* did not match 'feature' */
-               state = SkipLine;
-               /* FALL THROUGH */
-
-            case SkipLine:
-            skipLine:
-               /* Skip everything until we see linefeed or carriage return */
-               if (ch != 10 && ch != 13)
-                  break;
-
-               state = StartLine;
-               break;
-
-            case Colon:
-               /* Match any number of space or tab followed by ':' */
-               if (ch == 32 || ch == 9)
-                  break;
-
-               if (ch == 58) /* i.e. ':' */
-               {
-                  state = StartTag;
-                  break;
-               }
-
-               /* Either a bad line format or a 'feature' prefix followed by
-                * other characters.
-                */
-               state = SkipLine;
-               goto skipLine;
-
-            case StartTag:
-               /* Skip space characters before a tag */
-               if (ch == 32 || ch == 9)
-                  break;
-
-               state = Neon;
-               counter = 0;
-               /* FALL THROUGH */
-
-            case Neon:
-               /* Look for 'neon' tag */
-               if ((ch & ~0x20) == ch_neon[counter])
-               {
-                  if (++counter == (sizeof ch_neon))
-                     state = HaveNeon;
-                  break;
-               }
-
-               state = SkipTag;
-               /* FALL THROUGH */
-
-            case SkipTag:
-               /* Skip non-space characters */
-               if (ch == 10 || ch == 13)
-                  state = StartLine;
-
-               else if (ch == 32 || ch == 9)
-                  state = StartTag;
-               break;
-
-            case HaveNeon:
-               /* Have seen a 'neon' prefix, but there must be a space or new
-                * line character to terminate it.
-                */
-               if (ch == 10 || ch == 13 || ch == 32 || ch == 9)
-               {
-                  fclose(f);
-                  return 1;
-               }
-
-               state = SkipTag;
-               break;
-
-            default:
-               png_error(png_ptr, "png_have_neon: internal error (bug)");
-         }
-      }
-   }
-
-#ifdef PNG_WARNINGS_SUPPORTED
-   else
-      png_warning(png_ptr, "/proc/cpuinfo open failed");
-#endif
-
-   return 0;
-}
diff --git a/contrib/conftest/README b/contrib/conftest/README
deleted file mode 100644
index 0f47279..0000000
--- a/contrib/conftest/README
+++ /dev/null
@@ -1,49 +0,0 @@
-This directory contains test configuration files, currently always '.dfa' files
-intended to be used in the build by setting the make macro DFA_XTRA to the name
-of the file.
-
-These files are used in release validation of the 'configure' builds of libpng
-by building 'make check', or 'make all-am' for cross-builds, with each .dfa
-file.
-
-The files in this directory may change between minor releases, however
-contributions describing specific builds of libpng are welcomed.  There is no
-guarantee that libpng will continue to build with such configurations; support
-for given configurations can be, and has been, dropped between successive minor
-releases.  However if a .dfa file describing a configuration is not in this
-directory it is very unlikely that it will be tested before a minor release!
-
-You can use these .dfa files as the basis of new configurations.  Files in this
-directory should not have any use restrictions or restrictive licenses.
-
-This directory is not included in the .zip and .7z distributions, which do
-not contain 'configure' scripts.
-
-DOCUMENTATION
-=============
-
-Examples:
-   ${srcdir}/pngusr.dfa
-   ${srcdir}/contrib/pngminim/*/pngusr.dfa
-
-Documentation of the options:
-   ${srcdir}/scripts/pnglibconf.dfa
-
-Documentation of the file format:
-   ${srcdir}/scripts/options.awk
-
-FILE NAMING
-===========
-
-File names in this directory may NOT contain any of the five characters:
-
-   - , + * ?
-
-Neither may they contain any space character.
-
-While other characters may be used it is strongly suggested that file names be
-limited to lower case Latiin alphabetic characters (a-z), digits (0-9) and, if
-necessary the underscore (_) character.  File names should be about 8 characters
-long (excluding the .dfa extension).  Submitted .dfa files should have names
-between 7 and 16 characters long, shorter names (6 characters or less) are
-reserved for standard tests.
diff --git a/contrib/conftest/pngcp.dfa b/contrib/conftest/pngcp.dfa
deleted file mode 100644
index 15a856e..0000000
--- a/contrib/conftest/pngcp.dfa
+++ /dev/null
@@ -1,57 +0,0 @@
-# pngcp.dfa
-#  Build time configuration of libpng
-#
-# Author: John Bowler
-# Copyright: (c) John Bowler, 2016
-# Usage rights:
-#  To the extent possible under law, the author has waived all copyright and
-#  related or neighboring rights to this work.  This work is published from:
-#  United States.
-#
-# Build libpng with support for pngcp.  This means just png_read_png,
-# png_write_png and small number of configuration settings.
-#
-everything = off
-
-# This option is specific to this configuration; it adds a #define to the
-# generated pnglibconf.h which turns on the (not portable) timing option for
-# pngcp.  Note that any option is automatically preceded by PNG_; there is no
-# way round this and this is deliberate.
-option PNGCP_TIMING
-
-# Because of the everything off above the option must also be turned on.  This
-# may not be done in one step because it is safer and avoids mis-spelled options
-# in user .dfa files to error out if an unrecognized option is turned on.
-option PNGCP_TIMING on
-
-# Options to turn on png_read_png and png_write_png:
-option INFO_IMAGE on
-option SEQUENTIAL_READ on
-option EASY_ACCESS on
-option WRITE on
-option WRITE_16BIT on
-option WRITE_FILTER on
-
-# pngcp needs this to preserve unknown chunks, switching all these on means that
-# pngcp can work without explicit known chunk reading suppport
-option UNKNOWN_CHUNKS on
-option SET_UNKNOWN_CHUNKS on
-option HANDLE_AS_UNKNOWN on
-option SAVE_UNKNOWN_CHUNKS on
-option WRITE_UNKNOWN_CHUNKS on
-
-# pngcp needs this to handle palette files with invalid indices:
-option CHECK_FOR_INVALID_INDEX on
-option GET_PALETTE_MAX on
-
-# Pre-libpng 1.7 pngcp has to stash text chunks manually, post 1.7 without this
-# text chunks should be handled as unknown ok.
-option TEXT on
-
-# this is used to turn off limits:
-option USER_LIMITS on
-option SET_USER_LIMITS on
-
-# these are are just required for specific customizations
-option WRITE_CUSTOMIZE_ZTXT_COMPRESSION on
-option WRITE_CUSTOMIZE_COMPRESSION on
diff --git a/contrib/conftest/read.dfa b/contrib/conftest/read.dfa
deleted file mode 100644
index 21e88d0..0000000
--- a/contrib/conftest/read.dfa
+++ /dev/null
@@ -1,58 +0,0 @@
-# read.dfa
-#  Build time configuration of libpng
-#
-# Author: John Bowler
-# Copyright: (c) John Bowler, 2013
-# Usage rights:
-#  To the extent possible under law, the author has waived all copyright and
-#  related or neighboring rights to this work.  This work is published from:
-#  United States.
-#
-# Build libpng with basic read support.  This enables the lowest level libpng
-# read API - the one where the calling code has to use a loop to read each row.
-# At present this is the API used by most programs.
-#
-# Support is enabled only for those chunks and transformations that are
-# typically required - others can be added easily.
-#
-
-everything = off
-
-# The sequential read code is enabled here; the progressive code can be used
-# instead but there is no point enabling both.
-
-option SEQUENTIAL_READ on
-
-# Likewise it is pointless enabling both fixed and floating point APIs.  Choose
-# one or the other for both the API and the internal math.
-
-#Fixed point:
-#option FIXED_POINT on
-#option FLOATING_ARITHMETIC off
-
-#Floating point:
-option FLOATING_POINT on
-option FLOATING_ARITHMETIC on
-
-# Basic error handling, IO and user memory support.  The latter allows the
-# application program to provide its own implementations of 'malloc' and 'free'.
-option SETJMP on
-option STDIO on
-option USER_MEM on
-
-# To read the full set of PNG images correctly interlace, transparency and
-# 16-bit support is required.  The application can implement interlace itself,
-# but very few do and it's no longer possible to disable it when READ is
-# enabled.
-option READ_tRNS on
-option READ_16BIT on
-
-# Everything else is application dependent.  This file assumes the app handles
-# all the native PNG bit layouts, so it doesn't need any of layout change
-# transforms, but needs libpng to perform gamma correction.  It doesn't do any
-# colorspace stuff and ignores the 'significant bit' information.
-#
-# If your app always expands the image to a limited set of bit layouts you
-# probably want to consider using the simplified API instead of the low level
-# one - see png.h and s_read.dfa.
-option READ_GAMMA on
diff --git a/contrib/conftest/s_read.dfa b/contrib/conftest/s_read.dfa
deleted file mode 100644
index cb1ce0b..0000000
--- a/contrib/conftest/s_read.dfa
+++ /dev/null
@@ -1,35 +0,0 @@
-# s_read.dfa
-#  Build time configuration of libpng
-#
-# Author: John Bowler
-# Copyright: (c) John Bowler, 2013
-# Usage rights:
-#  To the extent possible under law, the author has waived all copyright and
-#  related or neighboring rights to this work.  This work is published from:
-#  United States.
-#
-# Build libpng with simplified read support (only).  This builds a minimal
-# libpng able to read all PNG formats and convert them into a small number of
-# well understood memory formats.
-#
-
-everything = off
-
-option SIMPLIFIED_READ on
-
-# It isn't necessary to chose fixed or floating point for the APIs because the
-# simplified API doesn't need fixed or floating point numbers.  It is necessary
-# to chose an internal math implementation.  The default (because of 'everything
-# = off') is fixed point - turn the floating point implementation on if you have
-# hardware floating point or prefer your software floating point implementation.
-option FLOATING_ARITHMETIC on
-
-# This is not strictly necessary, but without it the message strings in the API
-# will not be filled in
-option ERROR_TEXT on
-
-# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
-# need this if you don't use them, they just allow the in-memory layout to be
-# changed to match common hardware formats.
-option SIMPLIFIED_READ_AFIRST on
-option SIMPLIFIED_READ_BGR on
diff --git a/contrib/conftest/s_write.dfa b/contrib/conftest/s_write.dfa
deleted file mode 100644
index e540a46..0000000
--- a/contrib/conftest/s_write.dfa
+++ /dev/null
@@ -1,33 +0,0 @@
-# s_write.dfa
-#  Build time configuration of libpng
-#
-# Author: John Bowler
-# Copyright: (c) John Bowler, 2013
-# Usage rights:
-#  To the extent possible under law, the author has waived all copyright and
-#  related or neighboring rights to this work.  This work is published from:
-#  United States.
-#
-# Build libpng with (just) simplified write support
-#
-
-everything = off
-
-option SIMPLIFIED_WRITE on
-
-# It isn't necessary to chose fixed or floating point for the APIs because the
-# simplified API doesn't need fixed or floating point numbers.  It is necessary
-# to chose an internal math implementation.  The default (because of 'everything
-# = off') is fixed point - turn the floating point implementation on if you have
-# hardware floating point or prefer your software floating point implementation.
-option FLOATING_ARITHMETIC on
-
-# This is not strictly necessary, but without it the message strings in the API
-# will not be filled in
-option ERROR_TEXT on
-
-# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
-# need this if you don't use them, they just allow the in-memory layout to be
-# changed to match common hardware formats.
-option SIMPLIFIED_WRITE_AFIRST on
-option SIMPLIFIED_WRITE_BGR on
diff --git a/contrib/conftest/simple.dfa b/contrib/conftest/simple.dfa
deleted file mode 100644
index 0419333..0000000
--- a/contrib/conftest/simple.dfa
+++ /dev/null
@@ -1,36 +0,0 @@
-# simple.dfa
-#  Build time configuration of libpng
-#
-# Author: John Bowler
-# Copyright: (c) John Bowler, 2013
-# Usage rights:
-#  To the extent possible under law, the author has waived all copyright and
-#  related or neighboring rights to this work.  This work is published from:
-#  United States.
-#
-# Build libpng with just the simplified APIs (read and write).
-#
-
-everything = off
-
-option SIMPLIFIED_WRITE on
-option SIMPLIFIED_READ on
-
-# It isn't necessary to chose fixed or floating point for the APIs because the
-# simplified API doesn't need fixed or floating point numbers.  It is necessary
-# to chose an internal math implementation.  The default (because of 'everything
-# = off') is fixed point - turn the floating point implementation on if you have
-# hardware floating point or prefer your software floating point implementation.
-option FLOATING_ARITHMETIC on
-
-# This is not strictly necessary, but without it the message strings in the API
-# will not be filled in
-option ERROR_TEXT on
-
-# Switching these options on enables the 'AFIRST' and 'BGR' formats - you don't
-# need this if you don't use them, they just allow the in-memory layout to be
-# changed to match common hardware formats.
-option SIMPLIFIED_READ_AFIRST on
-option SIMPLIFIED_READ_BGR on
-option SIMPLIFIED_WRITE_AFIRST on
-option SIMPLIFIED_WRITE_BGR on
diff --git a/contrib/conftest/write.dfa b/contrib/conftest/write.dfa
deleted file mode 100644
index 3319aab..0000000
--- a/contrib/conftest/write.dfa
+++ /dev/null
@@ -1,45 +0,0 @@
-# write.dfa
-#  Build time configuration of libpng
-#
-# Author: John Bowler
-# Copyright: (c) John Bowler, 2013
-# Usage rights:
-#  To the extent possible under law, the author has waived all copyright and
-#  related or neighboring rights to this work.  This work is published from:
-#  United States.
-#
-# Build libpng with no read support and minimal write support.
-#
-
-everything = off
-
-# Switch on the write code - this makes a minimalist encoder
-
-option WRITE on
-
-# Choose fixed or floating point APIs and arithmetic.  The choices are
-# independent but normally they will match.  It is typically better to use the
-# floating point if you have floating point hardware.  If you don't know, or
-# (perhaps) to make libpng smaller used fixed point throughout.
-
-#Fixed point:
-#option FIXED_POINT on
-#option FLOATING_ARITHMETIC off
-
-#Floating point:
-option FLOATING_POINT on
-option FLOATING_ARITHMETIC on
-
-# Basic error handling, IO and user memory support.  The latter allows the
-# application program to provide its own implementations of 'malloc' and 'free'.
-option SETJMP on
-option STDIO on
-option USER_MEM on
-
-# Everything else is optional.  Unlike the read code in libpng the write code
-# does not need to deal with arbitrary formats, so only add support for things
-# you really do write!  For example you might only write sRGB images, sometimes
-# with transparency and never write 16 bit images, so:
-option WRITE_sRGB on
-option WRITE_tRNS on
-#option WRITE_16BIT off (this is the default with 'everything = off')
diff --git a/contrib/examples/README.txt b/contrib/examples/README.txt
deleted file mode 100644
index 0525c9d..0000000
--- a/contrib/examples/README.txt
+++ /dev/null
@@ -1,24 +0,0 @@
-
-This directory (contrib/examples) contains examples of libpng usage.
-
-NO COPYRIGHT RIGHTS ARE CLAIMED TO ANY OF THE FILES IN THIS DIRECTORY.
-
-To the extent possible under law, the authors have waived all copyright and
-related or neighboring rights to this work.  This work is published from:
-United States.
-
-The files may be used freely in any way.  The intention is that appropriate
-parts of the files be used in other libpng-using programs without any need for
-the authors of the using code to seek copyright or license from the original
-authors.
-
-The source code and comments in this directory are the original work of the
-people named below.  No other person or organization has made contributions to
-the work in this directory.
-
-ORIGINAL AUTHORS
-    The following people have contributed to the code in this directory.  None
-    of the people below claim any rights with regard to the contents of this
-    directory.
-
-    John Bowler <jbowler@acm.org>
diff --git a/contrib/examples/iccfrompng.c b/contrib/examples/iccfrompng.c
deleted file mode 100644
index 603037e..0000000
--- a/contrib/examples/iccfrompng.c
+++ /dev/null
@@ -1,185 +0,0 @@
-/*- iccfrompng
- *
- * COPYRIGHT: Written by John Cunningham Bowler, 2011.
- * To the extent possible under law, the author has waived all copyright and
- * related or neighboring rights to this work.  This work is published from:
- * United States.
- *
- * Extract any icc profiles found in the given PNG files.  This is a simple
- * example of a program that extracts information from the header of a PNG file
- * without processing the image.  Notice that some header information may occur
- * after the image data. Textual data and comments are an example; the approach
- * in this file won't work reliably for such data because it only looks for the
- * information in the section of the file that preceeds the image data.
- *
- * Compile and link against libpng and zlib, plus anything else required on the
- * system you use.
- *
- * To use supply a list of PNG files containing iCCP chunks, the chunks will be
- * extracted to a similarly named file with the extension replaced by 'icc',
- * which will be overwritten without warning.
- */
-#include <stdlib.h>
-#include <setjmp.h>
-#include <string.h>
-#include <stdio.h>
-
-#include <png.h>
-
-#if defined(PNG_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED) && \
-    defined (PNG_iCCP_SUPPORTED)
-
-
-static int verbose = 1;
-static png_byte no_profile[] = "no profile";
-
-static png_bytep
-extract(FILE *fp, png_uint_32 *proflen)
-{
-   png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0,0,0);
-   png_infop info_ptr = NULL;
-   png_bytep result = NULL;
-
-   /* Initialize for error or no profile: */
-   *proflen = 0;
-
-   if (png_ptr == NULL)
-   {
-      fprintf(stderr, "iccfrompng: version library mismatch?\n");
-      return 0;
-   }
-
-   if (setjmp(png_jmpbuf(png_ptr)))
-   {
-      png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-      return 0;
-   }
-
-   png_init_io(png_ptr, fp);
-
-   info_ptr = png_create_info_struct(png_ptr);
-   if (info_ptr == NULL)
-      png_error(png_ptr, "OOM allocating info structure");
-
-   png_read_info(png_ptr, info_ptr);
-
-   {
-      png_charp name;
-      int compression_type;
-      png_bytep profile;
-
-      if (png_get_iCCP(png_ptr, info_ptr, &name, &compression_type, &profile,
-         proflen) & PNG_INFO_iCCP)
-      {
-         result = malloc(*proflen);
-         if (result != NULL)
-            memcpy(result, profile, *proflen);
-
-         else
-            png_error(png_ptr, "OOM allocating profile buffer");
-      }
-
-      else
-	result = no_profile;
-   }
-
-   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-   return result;
-}
-
-static int
-extract_one_file(const char *filename)
-{
-   int result = 0;
-   FILE *fp = fopen(filename, "rb");
-
-   if (fp != NULL)
-   {
-      png_uint_32 proflen = 0;
-      png_bytep profile = extract(fp, &proflen);
-
-      if (profile != NULL && profile != no_profile)
-      {
-         size_t len;
-         char *output;
-
-         {
-            const char *ep = strrchr(filename, '.');
-
-            if (ep != NULL)
-               len = ep-filename;
-
-            else
-               len = strlen(filename);
-         }
-
-         output = malloc(len + 5);
-         if (output != NULL)
-         {
-            FILE *of;
-
-            memcpy(output, filename, len);
-            strcpy(output+len, ".icc");
-
-            of = fopen(output, "wb");
-            if (of != NULL)
-            {
-               if (fwrite(profile, proflen, 1, of) == 1 &&
-                  fflush(of) == 0 &&
-                  fclose(of) == 0)
-               {
-                  if (verbose)
-                     printf("%s -> %s\n", filename, output);
-                  /* Success return */
-                  result = 1;
-               }
-
-               else
-               {
-                  fprintf(stderr, "%s: error writing profile\n", output);
-                  if (remove(output))
-                     fprintf(stderr, "%s: could not remove file\n", output);
-               }
-            }
-
-            else
-               fprintf(stderr, "%s: failed to open output file\n", output);
-
-            free(output);
-         }
-
-         else
-            fprintf(stderr, "%s: OOM allocating string!\n", filename);
-
-         free(profile);
-      }
-
-      else if (verbose && profile == no_profile)
-	printf("%s has no profile\n", filename);
-   }
-
-   else
-      fprintf(stderr, "%s: could not open file\n", filename);
-
-   return result;
-}
-
-int
-main(int argc, char **argv)
-{
-   int i;
-   int extracted = 0;
-
-   for (i=1; i<argc; ++i)
-   {
-      if (strcmp(argv[i], "-q") == 0)
-         verbose = 0;
-
-      else if (extract_one_file(argv[i]))
-         extracted = 1;
-   }
-
-   /* Exit code is true if any extract succeeds */
-   return extracted == 0;
-}
-#endif /* READ && STDIO && iCCP */
diff --git a/contrib/examples/pngpixel.c b/contrib/examples/pngpixel.c
deleted file mode 100644
index f762379..0000000
--- a/contrib/examples/pngpixel.c
+++ /dev/null
@@ -1,371 +0,0 @@
-/*- pngpixel
- *
- * COPYRIGHT: Written by John Cunningham Bowler, 2011.
- * To the extent possible under law, the author has waived all copyright and
- * related or neighboring rights to this work.  This work is published from:
- * United States.
- *
- * Read a single pixel value from a PNG file.
- *
- * This code illustrates basic 'by-row' reading of a PNG file using libpng.
- * Rows are read until a particular pixel is found; the value of this pixel is
- * then printed on stdout.
- *
- * The code illustrates how to do this on interlaced as well as non-interlaced
- * images.  Normally you would call png_set_interlace_handling() to have libpng
- * deal with the interlace for you, but that obliges you to buffer half of the
- * image to assemble the interlaced rows.  In this code
- * png_set_interlace_handling() is not called and, instead, the code handles the
- * interlace passes directly looking for the required pixel.
- */
-#include <stdlib.h>
-#include <stdio.h>
-#include <setjmp.h> /* required for error handling */
-
-/* Normally use <png.h> here to get the installed libpng, but this is done to
- * ensure the code picks up the local libpng implementation:
- */
-#include "../../png.h"
-
-#if defined(PNG_READ_SUPPORTED) && defined(PNG_SEQUENTIAL_READ_SUPPORTED)
-
-/* Return component 'c' of pixel 'x' from the given row. */
-static unsigned int
-component(png_const_bytep row, png_uint_32 x, unsigned int c,
-   unsigned int bit_depth, unsigned int channels)
-{
-   /* PNG images can be up to 2^31 pixels wide, but this means they can be up to
-    * 2^37 bits wide (for a 64-bit pixel - the largest possible) and hence 2^34
-    * bytes wide.  Since the row fitted into memory, however, the following must
-    * work:
-    */
-   png_uint_32 bit_offset_hi = bit_depth * ((x >> 6) * channels);
-   png_uint_32 bit_offset_lo = bit_depth * ((x & 0x3f) * channels + c);
-
-   row = (png_const_bytep)(((PNG_CONST png_byte (*)[8])row) + bit_offset_hi);
-   row += bit_offset_lo >> 3;
-   bit_offset_lo &= 0x07;
-
-   /* PNG pixels are packed into bytes to put the first pixel in the highest
-    * bits of the byte and into two bytes for 16-bit values with the high 8 bits
-    * first, so:
-    */
-   switch (bit_depth)
-   {
-      case 1: return (row[0] >> (7-bit_offset_lo)) & 0x01;
-      case 2: return (row[0] >> (6-bit_offset_lo)) & 0x03;
-      case 4: return (row[0] >> (4-bit_offset_lo)) & 0x0f;
-      case 8: return row[0];
-      case 16: return (row[0] << 8) + row[1];
-      default:
-         /* This should never happen; it indicates a bug in this program or in
-          * libpng itself:
-          */
-         fprintf(stderr, "pngpixel: invalid bit depth %u\n", bit_depth);
-         exit(1);
-   }
-}
-
-/* Print a pixel from a row returned by libpng; determine the row format, find
- * the pixel, and print the relevant information to stdout.
- */
-static void
-print_pixel(png_structp png_ptr, png_infop info_ptr, png_const_bytep row,
-   png_uint_32 x)
-{
-   PNG_CONST unsigned int bit_depth = png_get_bit_depth(png_ptr, info_ptr);
-
-   switch (png_get_color_type(png_ptr, info_ptr))
-   {
-      case PNG_COLOR_TYPE_GRAY:
-         printf("GRAY %u\n", component(row, x, 0, bit_depth, 1));
-         return;
-
-      /* The palette case is slightly more difficult - the palette and, if
-       * present, the tRNS ('transparency', though the values are really
-       * opacity) data must be read to give the full picture:
-       */
-      case PNG_COLOR_TYPE_PALETTE:
-         {
-            PNG_CONST int index = component(row, x, 0, bit_depth, 1);
-            png_colorp palette = NULL;
-            int num_palette = 0;
-
-            if ((png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) &
-               PNG_INFO_PLTE) && num_palette > 0 && palette != NULL)
-            {
-               png_bytep trans_alpha = NULL;
-               int num_trans = 0;
-               if ((png_get_tRNS(png_ptr, info_ptr, &trans_alpha, &num_trans,
-                  NULL) & PNG_INFO_tRNS) && num_trans > 0 &&
-                  trans_alpha != NULL)
-                  printf("INDEXED %u = %d %d %d %d\n", index,
-                     palette[index].red, palette[index].green,
-                     palette[index].blue,
-                     index < num_trans ? trans_alpha[index] : 255);
-
-               else /* no transparency */
-                  printf("INDEXED %u = %d %d %d\n", index,
-                     palette[index].red, palette[index].green,
-                     palette[index].blue);
-            }
-
-            else
-               printf("INDEXED %u = invalid index\n", index);
-         }
-         return;
-
-      case PNG_COLOR_TYPE_RGB:
-         printf("RGB %u %u %u\n", component(row, x, 0, bit_depth, 3),
-            component(row, x, 1, bit_depth, 3),
-            component(row, x, 2, bit_depth, 3));
-         return;
-
-      case PNG_COLOR_TYPE_GRAY_ALPHA:
-         printf("GRAY+ALPHA %u %u\n", component(row, x, 0, bit_depth, 2),
-            component(row, x, 1, bit_depth, 2));
-         return;
-
-      case PNG_COLOR_TYPE_RGB_ALPHA:
-         printf("RGBA %u %u %u %u\n", component(row, x, 0, bit_depth, 4),
-            component(row, x, 1, bit_depth, 4),
-            component(row, x, 2, bit_depth, 4),
-            component(row, x, 3, bit_depth, 4));
-         return;
-
-      default:
-         png_error(png_ptr, "pngpixel: invalid color type");
-   }
-}
-
-int main(int argc, const char **argv)
-{
-   /* This program uses the default, <setjmp.h> based, libpng error handling
-    * mechanism, therefore any local variable that exists before the call to
-    * setjmp and is changed after the call to setjmp returns successfully must
-    * be declared with 'volatile' to ensure that their values don't get
-    * destroyed by longjmp:
-    */
-   volatile int result = 1/*fail*/;
-
-   if (argc == 4)
-   {
-      long x = atol(argv[1]);
-      long y = atol(argv[2]);
-      FILE *f = fopen(argv[3], "rb");
-      volatile png_bytep row = NULL;
-
-      if (f != NULL)
-      {
-         /* libpng requires a callback function for handling errors; this
-          * callback must not return.  The default callback function uses a
-          * stored <setjmp.h> style jmp_buf which is held in a png_struct and
-          * writes error messages to stderr.  Creating the png_struct is a
-          * little tricky; just copy the following code.
-          */
-         png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
-            NULL, NULL, NULL);
-
-         if (png_ptr != NULL)
-         {
-            png_infop info_ptr = png_create_info_struct(png_ptr);
-
-            if (info_ptr != NULL)
-            {
-               /* Declare stack variables to hold pointers to locally allocated
-                * data.
-                */
-
-               /* Initialize the error control buffer: */
-               if (setjmp(png_jmpbuf(png_ptr)) == 0)
-               {
-                  png_uint_32 width, height;
-                  int bit_depth, color_type, interlace_method,
-                     compression_method, filter_method;
-                  png_bytep row_tmp;
-
-                  /* Now associate the recently opened (FILE*) with the default
-                   * libpng initialization functions.  Sometimes libpng is
-                   * compiled without stdio support (it can be difficult to do
-                   * in some environments); in that case you will have to write
-                   * your own read callback to read data from the (FILE*).
-                   */
-                  png_init_io(png_ptr, f);
-
-                  /* And read the first part of the PNG file - the header and
-                   * all the information up to the first pixel.
-                   */
-                  png_read_info(png_ptr, info_ptr);
-
-                  /* This fills in enough information to tell us the width of
-                   * each row in bytes, allocate the appropriate amount of
-                   * space.  In this case png_malloc is used - it will not
-                   * return if memory isn't available.
-                   */
-                  row = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
-                     info_ptr));
-
-                  /* To avoid the overhead of using a volatile auto copy row_tmp
-                   * to a local here - just use row for the png_free below.
-                   */
-                  row_tmp = row;
-
-                  /* All the information we need is in the header is returned by
-                   * png_get_IHDR, if this fails we can now use 'png_error' to
-                   * signal the error and return control to the setjmp above.
-                   */
-                  if (png_get_IHDR(png_ptr, info_ptr, &width, &height,
-                     &bit_depth, &color_type, &interlace_method,
-                     &compression_method, &filter_method))
-                  {
-                     int passes, pass;
-
-                     /* png_set_interlace_handling returns the number of
-                      * passes required as well as turning on libpng's
-                      * handling, but since we do it ourselves this is
-                      * necessary:
-                      */
-                     switch (interlace_method)
-                     {
-                        case PNG_INTERLACE_NONE:
-                           passes = 1;
-                           break;
-
-                        case PNG_INTERLACE_ADAM7:
-                           passes = PNG_INTERLACE_ADAM7_PASSES;
-                           break;
-
-                        default:
-                           png_error(png_ptr, "pngpixel: unknown interlace");
-                     }
-
-                     /* Now read the pixels, pass-by-pass, row-by-row: */
-                     png_start_read_image(png_ptr);
-
-                     for (pass=0; pass<passes; ++pass)
-                     {
-                        png_uint_32 ystart, xstart, ystep, xstep;
-                        png_uint_32 py;
-
-                        if (interlace_method == PNG_INTERLACE_ADAM7)
-                        {
-                           /* Sometimes the whole pass is empty because the
-                            * image is too narrow or too short.  libpng
-                            * expects to be called for each row that is
-                            * present in the pass, so it may be necessary to
-                            * skip the loop below (over py) if the image is
-                            * too narrow.
-                            */
-                           if (PNG_PASS_COLS(width, pass) == 0)
-                              continue;
-
-                           /* We need the starting pixel and the offset
-                            * between each pixel in this pass; use the macros
-                            * in png.h:
-                            */
-                           xstart = PNG_PASS_START_COL(pass);
-                           ystart = PNG_PASS_START_ROW(pass);
-                           xstep = PNG_PASS_COL_OFFSET(pass);
-                           ystep = PNG_PASS_ROW_OFFSET(pass);
-                        }
-
-                        else
-                        {
-                           ystart = xstart = 0;
-                           ystep = xstep = 1;
-                        }
-
-                        /* To find the pixel, loop over 'py' for each pass
-                         * reading a row and then checking to see if it
-                         * contains the pixel.
-                         */
-                        for (py = ystart; py < height; py += ystep)
-                        {
-                           png_uint_32 px, ppx;
-
-                           /* png_read_row takes two pointers.  When libpng
-                            * handles the interlace the first is filled in
-                            * pixel-by-pixel, and the second receives the same
-                            * pixels but they are replicated across the
-                            * unwritten pixels so far for each pass.  When we
-                            * do the interlace, however, they just contain
-                            * the pixels from the interlace pass - giving
-                            * both is wasteful and pointless, so we pass a
-                            * NULL pointer.
-                            */
-                           png_read_row(png_ptr, row_tmp, NULL);
-
-                           /* Now find the pixel if it is in this row; there
-                            * are, of course, much better ways of doing this
-                            * than using a for loop:
-                            */
-                           if (y == py) for (px = xstart, ppx = 0;
-                              px < width; px += xstep, ++ppx) if (x == px)
-                           {
-                              /* 'ppx' is the index of the pixel in the row
-                               * buffer.
-                               */
-                              print_pixel(png_ptr, info_ptr, row_tmp, ppx);
-
-                              /* Now terminate the loops early - we have
-                               * found and handled the required data.
-                               */
-                              goto pass_loop_end;
-                           } /* x loop */
-                        } /* y loop */
-                     } /* pass loop */
-
-                     /* Finally free the temporary buffer: */
-                  pass_loop_end:
-                     row = NULL;
-                     png_free(png_ptr, row_tmp);
-                  }
-
-                  else
-                     png_error(png_ptr, "pngpixel: png_get_IHDR failed");
-
-               }
-
-               else
-               {
-                  /* Else libpng has raised an error.  An error message has
-                   * already been output, so it is only necessary to clean up
-                   * locally allocated data:
-                   */
-                  if (row != NULL)
-                  {
-                     /* The default implementation of png_free never errors out
-                      * (it just crashes if something goes wrong), but the safe
-                      * way of using it is still to clear 'row' before calling
-                      * png_free:
-                      */
-                     png_bytep row_tmp = row;
-                     row = NULL;
-                     png_free(png_ptr, row_tmp);
-                  }
-               }
-
-               png_destroy_info_struct(png_ptr, &info_ptr);
-            }
-
-            else
-               fprintf(stderr, "pngpixel: out of memory allocating png_info\n");
-
-            png_destroy_read_struct(&png_ptr, NULL, NULL);
-         }
-
-         else
-            fprintf(stderr, "pngpixel: out of memory allocating png_struct\n");
-      }
-
-      else
-         fprintf(stderr, "pngpixel: %s: could not open file\n", argv[3]);
-   }
-
-   else
-      /* Wrong number of arguments */
-      fprintf(stderr, "pngpixel: usage: pngpixel x y png-file\n");
-
-   return result;
-}
-#endif /* READ && SEQUENTIAL_READ */
diff --git a/contrib/examples/pngtopng.c b/contrib/examples/pngtopng.c
deleted file mode 100644
index 4acf6b3..0000000
--- a/contrib/examples/pngtopng.c
+++ /dev/null
@@ -1,95 +0,0 @@
-/*- pngtopng
- *
- * COPYRIGHT: Written by John Cunningham Bowler, 2011.
- * To the extent possible under law, the author has waived all copyright and
- * related or neighboring rights to this work.  This work is published from:
- * United States.
- *
- * Read a PNG and write it out in a fixed format, using the 'simplified API'
- * that was introduced in libpng-1.6.0.
- *
- * This sample code is just the code from the top of 'example.c' with some error
- * handling added.  See example.c for more comments.
- */
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-
-/* Normally use <png.h> here to get the installed libpng, but this is done to
- * ensure the code picks up the local libpng implementation:
- */
-#include "../../png.h"
-#if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && \
-    defined(PNG_SIMPLIFIED_WRITE_SUPPORTED)
-
-int main(int argc, const char **argv)
-{
-   int result = 1;
-
-   if (argc == 3)
-   {
-      png_image image;
-
-      /* Only the image structure version number needs to be set. */
-      memset(&image, 0, sizeof image);
-      image.version = PNG_IMAGE_VERSION;
-
-      if (png_image_begin_read_from_file(&image, argv[1]))
-      {
-         png_bytep buffer;
-
-         /* Change this to try different formats!  If you set a colormap format
-          * then you must also supply a colormap below.
-          */
-         image.format = PNG_FORMAT_RGBA;
-
-         buffer = malloc(PNG_IMAGE_SIZE(image));
-
-         if (buffer != NULL)
-         {
-            if (png_image_finish_read(&image, NULL/*background*/, buffer,
-               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
-            {
-               if (png_image_write_to_file(&image, argv[2],
-                  0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
-                  NULL/*colormap*/))
-                  result = 0;
-
-               else
-                  fprintf(stderr, "pngtopng: write %s: %s\n", argv[2],
-                      image.message);
-
-               free(buffer);
-            }
-
-            else
-            {
-               fprintf(stderr, "pngtopng: read %s: %s\n", argv[1],
-                   image.message);
-
-               /* This is the only place where a 'free' is required; libpng does
-                * the cleanup on error and success, but in this case we couldn't
-                * complete the read because of running out of memory.
-                */
-               png_image_free(&image);
-            }
-         }
-
-         else
-            fprintf(stderr, "pngtopng: out of memory: %lu bytes\n",
-               (unsigned long)PNG_IMAGE_SIZE(image));
-      }
-
-      else
-         /* Failed to read the first argument: */
-         fprintf(stderr, "pngtopng: %s: %s\n", argv[1], image.message);
-   }
-
-   else
-      /* Wrong number of arguments */
-      fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
-
-   return result;
-}
-#endif /* READ && WRITE */
diff --git a/contrib/examples/simpleover.c b/contrib/examples/simpleover.c
deleted file mode 100644
index 59dd313..0000000
--- a/contrib/examples/simpleover.c
+++ /dev/null
@@ -1,648 +0,0 @@
-/*- simpleover
- *
- * COPYRIGHT: Written by John Cunningham Bowler, 2015.
- * To the extent possible under law, the author has waived all copyright and
- * related or neighboring rights to this work.  This work is published from:
- * United States.
- *
- * Read several PNG files, which should have an alpha channel or transparency
- * information, and composite them together to produce one or more 16-bit linear
- * RGBA intermediates.  This involves doing the correct 'over' composition to
- * combine the alpha channels and corresponding data.
- *
- * Finally read an output (background) PNG using the 24-bit RGB format (the
- * PNG will be composited on green (#00ff00) by default if it has an alpha
- * channel), and apply the intermediate image generated above to specified
- * locations in the image.
- *
- * The command line has the general format:
- *
- *    simpleover <background.png> [output.png]
- *        {--sprite=width,height,name {[--at=x,y] {sprite.png}}}
- *        {--add=name {x,y}}
- *
- * The --sprite and --add options may occur multiple times. They are executed
- * in order.  --add may refer to any sprite already read.
- *
- * This code is intended to show how to composite multiple images together
- * correctly.  Apart from the libpng Simplified API the only work done in here
- * is to combine multiple input PNG images into a single sprite; this involves
- * a Porter-Duff 'over' operation and the input PNG images may, as a result,
- * be regarded as being layered one on top of the other with the first (leftmost
- * on the command line) being at the bottom and the last on the top.
- */
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
-#include <stdio.h>
-#include <errno.h>
-
-/* Normally use <png.h> here to get the installed libpng, but this is done to
- * ensure the code picks up the local libpng implementation, so long as this
- * file is linked against a sufficiently recent libpng (1.6+) it is ok to
- * change this to <png.h>:
- */
-#include "../../png.h"
-
-#ifdef PNG_SIMPLIFIED_READ_SUPPORTED
-
-#define sprite_name_chars 15
-struct sprite {
-   FILE         *file;
-   png_uint_16p  buffer;
-   unsigned int  width;
-   unsigned int  height;
-   char          name[sprite_name_chars+1];
-};
-
-#if 0 /* div by 65535 test program */
-#include <math.h>
-#include <stdio.h>
-
-int main(void) {
-   double err = 0;
-   unsigned int xerr = 0;
-   unsigned int r = 32769;
-   {
-      unsigned int x = 0;
-
-      do {
-         unsigned int t = x + (x >> 16) /*+ (x >> 31)*/ + r;
-         double v = x, errtest;
-
-         if (t < x) {
-            fprintf(stderr, "overflow: %u+%u -> %u\n", x, r, t);
-            return 1;
-         }
-
-         v /= 65535;
-         errtest = v;
-         t >>= 16;
-         errtest -= t;
-
-         if (errtest > err) {
-            err = errtest;
-            xerr = x;
-
-            if (errtest >= .5) {
-               fprintf(stderr, "error: %u/65535 = %f, not %u, error %f\n",
-                     x, v, t, errtest);
-               return 0;
-            }
-         }
-      } while (++x <= 65535U*65535U);
-   }
-
-   printf("error %f @ %u\n", err, xerr);
-
-   return 0;
-}
-#endif /* div by 65535 test program */
-
-static void
-sprite_op(const struct sprite *sprite, int x_offset, int y_offset,
-   png_imagep image, const png_uint_16 *buffer)
-{
-   /* This is where the Porter-Duff 'Over' operator is evaluated; change this
-    * code to change the operator (this could be parameterized).  Any other
-    * image processing operation could be used here.
-    */
-
-
-   /* Check for an x or y offset that pushes any part of the image beyond the
-    * right or bottom of the sprite:
-    */
-   if ((y_offset < 0 || (unsigned)/*SAFE*/y_offset < sprite->height) &&
-       (x_offset < 0 || (unsigned)/*SAFE*/x_offset < sprite->width))
-   {
-      unsigned int y = 0;
-
-      if (y_offset < 0)
-         y = -y_offset; /* Skip to first visible row */
-
-      do
-      {
-         unsigned int x = 0;
-
-         if (x_offset < 0)
-            x = -x_offset;
-
-         do
-         {
-            /* In and out are RGBA values, so: */
-            const png_uint_16 *in_pixel = buffer + (y * image->width + x)*4;
-            png_uint_32 in_alpha = in_pixel[3];
-
-            /* This is the optimized Porter-Duff 'Over' operation, when the
-             * input alpha is 0 the output is not changed.
-             */
-            if (in_alpha > 0)
-            {
-               png_uint_16 *out_pixel = sprite->buffer +
-                  ((y+y_offset) * sprite->width + (x+x_offset))*4;
-
-               /* This is the weight to apply to the output: */
-               in_alpha = 65535-in_alpha;
-
-               if (in_alpha > 0)
-               {
-                  /* The input must be composed onto the output. This means
-                   * multiplying the current output pixel value by the inverse
-                   * of the input alpha (1-alpha). A division is required but
-                   * it is by the constant 65535.  Approximate this as:
-                   *
-                   *     (x + (x >> 16) + 32769) >> 16;
-                   *
-                   * This is exact (and does not overflow) for all values of
-                   * x in the range 0..65535*65535.  (Note that the calculation
-                   * produces the closest integer; the maximum error is <0.5).
-                   */
-                  png_uint_32 tmp;
-
-#                 define compose(c)\
-                     tmp = out_pixel[c] * in_alpha;\
-                     tmp = (tmp + (tmp >> 16) + 32769) >> 16;\
-                     out_pixel[c] = tmp + in_pixel[c]
-
-                  /* The following is very vectorizable... */
-                  compose(0);
-                  compose(1);
-                  compose(2);
-                  compose(3);
-               }
-
-               else
-                  out_pixel[0] = in_pixel[0],
-                  out_pixel[1] = in_pixel[1],
-                  out_pixel[2] = in_pixel[2],
-                  out_pixel[3] = in_pixel[3];
-            }
-         }
-         while (++x < image->width);
-      }
-      while (++y < image->height);
-   }
-}
-
-static int
-create_sprite(struct sprite *sprite, int *argc, const char ***argv)
-{
-   /* Read the arguments and create this sprite. The sprite buffer has already
-    * been allocated. This reads the input PNGs one by one in linear format,
-    * composes them onto the sprite buffer (the code in the function above)
-    * then saves the result, converting it on the fly to PNG RGBA 8-bit format.
-    */
-   while (*argc > 0)
-   {
-      char tombstone;
-      int x = 0, y = 0;
-
-      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
-      {
-         /* The only supported option is --at. */
-         if (sscanf((*argv)[0], "--at=%d,%d%c", &x, &y, &tombstone) != 2)
-            break; /* success; caller will parse this option */
-
-         ++*argv, --*argc;
-      }
-
-      else
-      {
-         /* The argument has to be a file name */
-         png_image image;
-
-         image.version = PNG_IMAGE_VERSION;
-         image.opaque = NULL;
-
-         if (png_image_begin_read_from_file(&image, (*argv)[0]))
-         {
-            png_uint_16p buffer;
-
-            image.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
-
-            buffer = malloc(PNG_IMAGE_SIZE(image));
-
-            if (buffer != NULL)
-            {
-               if (png_image_finish_read(&image, NULL/*background*/, buffer,
-                  0/*row_stride*/,
-                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
-               {
-                  /* This is the place where the Porter-Duff 'Over' operator
-                   * needs to be done by this code.  In fact, any image
-                   * processing required can be done here; the data is in
-                   * the correct format (linear, 16-bit) and source and
-                   * destination are in memory.
-                   */
-                  sprite_op(sprite, x, y, &image, buffer);
-                  free(buffer);
-                  ++*argv, --*argc;
-                  /* And continue to the next argument */
-                  continue;
-               }
-
-               else
-               {
-                  free(buffer);
-                  fprintf(stderr, "simpleover: read %s: %s\n", (*argv)[0],
-                      image.message);
-               }
-            }
-
-            else
-            {
-               fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
-                  (unsigned long)PNG_IMAGE_SIZE(image));
-
-               /* png_image_free must be called if we abort the Simplified API
-                * read because of a problem detected in this code.  If problems
-                * are detected in the Simplified API it cleans up itself.
-                */
-               png_image_free(&image);
-            }
-         }
-
-         else
-         {
-            /* Failed to read the first argument: */
-            fprintf(stderr, "simpleover: %s: %s\n", (*argv)[0], image.message);
-         }
-
-         return 0; /* failure */
-      }
-   }
-
-   /* All the sprite operations have completed successfully. Save the RGBA
-    * buffer as a PNG using the simplified write API.
-    */
-   sprite->file = tmpfile();
-
-   if (sprite->file != NULL)
-   {
-      png_image save;
-
-      memset(&save, 0, sizeof save);
-      save.version = PNG_IMAGE_VERSION;
-      save.opaque = NULL;
-      save.width = sprite->width;
-      save.height = sprite->height;
-      save.format = PNG_FORMAT_LINEAR_RGB_ALPHA;
-      save.flags = PNG_IMAGE_FLAG_FAST;
-      save.colormap_entries = 0;
-
-      if (png_image_write_to_stdio(&save, sprite->file, 1/*convert_to_8_bit*/,
-          sprite->buffer, 0/*row_stride*/, NULL/*colormap*/))
-      {
-         /* Success; the buffer is no longer needed: */
-         free(sprite->buffer);
-         sprite->buffer = NULL;
-         return 1; /* ok */
-      }
-
-      else
-         fprintf(stderr, "simpleover: write sprite %s: %s\n", sprite->name,
-            save.message);
-   }
-
-   else
-      fprintf(stderr, "simpleover: sprite %s: could not allocate tmpfile: %s\n",
-         sprite->name, strerror(errno));
-
-   return 0; /* fail */
-}
-
-static int
-add_sprite(png_imagep output, png_bytep out_buf, struct sprite *sprite,
-   int *argc, const char ***argv)
-{
-   /* Given a --add argument naming this sprite, perform the operations listed
-    * in the following arguments.  The arguments are expected to have the form
-    * (x,y), which is just an offset at which to add the sprite to the
-    * output.
-    */
-   while (*argc > 0)
-   {
-      char tombstone;
-      int x, y;
-
-      if ((*argv)[0][0] == '-' && (*argv)[0][1] == '-')
-         return 1; /* success */
-
-      if (sscanf((*argv)[0], "%d,%d%c", &x, &y, &tombstone) == 2)
-      {
-         /* Now add the new image into the sprite data, but only if it
-          * will fit.
-          */
-         if (x < 0 || y < 0 ||
-             (unsigned)/*SAFE*/x >= output->width ||
-             (unsigned)/*SAFE*/y >= output->height ||
-             sprite->width > output->width-x ||
-             sprite->height > output->height-y)
-         {
-            fprintf(stderr, "simpleover: sprite %s @ (%d,%d) outside image\n",
-               sprite->name, x, y);
-            /* Could just skip this, but for the moment it is an error */
-            return 0; /* error */
-         }
-
-         else
-         {
-            /* Since we know the sprite fits we can just read it into the
-             * output using the simplified API.
-             */
-            png_image in;
-
-            in.version = PNG_IMAGE_VERSION;
-            rewind(sprite->file);
-
-            if (png_image_begin_read_from_stdio(&in, sprite->file))
-            {
-               in.format = PNG_FORMAT_RGB; /* force compose */
-
-               if (png_image_finish_read(&in, NULL/*background*/,
-                  out_buf + (y*output->width + x)*3/*RGB*/,
-                  output->width*3/*row_stride*/,
-                  NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP*/))
-               {
-                  ++*argv, --*argc;
-                  continue;
-               }
-            }
-
-            /* The read failed: */
-            fprintf(stderr, "simpleover: add sprite %s: %s\n", sprite->name,
-                in.message);
-            return 0; /* error */
-         }
-      }
-
-      else
-      {
-         fprintf(stderr, "simpleover: --add='%s': invalid position %s\n",
-               sprite->name, (*argv)[0]);
-         return 0; /* error */
-      }
-   }
-
-   return 1; /* ok */
-}
-
-static int
-simpleover_process(png_imagep output, png_bytep out_buf, int argc,
-   const char **argv)
-{
-   int result = 1; /* success */
-#  define csprites 10/*limit*/
-#  define str(a) #a
-   int nsprites = 0;
-   struct sprite sprites[csprites];
-
-   while (argc > 0)
-   {
-      result = 0; /* fail */
-
-      if (strncmp(argv[0], "--sprite=", 9) == 0)
-      {
-         char tombstone;
-
-         if (nsprites < csprites)
-         {
-            int n;
-
-            sprites[nsprites].width = sprites[nsprites].height = 0;
-            sprites[nsprites].name[0] = 0;
-
-            n = sscanf(argv[0], "--sprite=%u,%u,%" str(sprite_name_chars) "s%c",
-                &sprites[nsprites].width, &sprites[nsprites].height,
-                sprites[nsprites].name, &tombstone);
-
-            if ((n == 2 || n == 3) &&
-                sprites[nsprites].width > 0 && sprites[nsprites].height > 0)
-            {
-               size_t buf_size, tmp;
-
-               /* Default a name if not given. */
-               if (sprites[nsprites].name[0] == 0)
-                  sprintf(sprites[nsprites].name, "sprite-%d", nsprites+1);
-
-               /* Allocate a buffer for the sprite and calculate the buffer
-                * size:
-                */
-               buf_size = sizeof (png_uint_16 [4]);
-               buf_size *= sprites[nsprites].width;
-               buf_size *= sprites[nsprites].height;
-
-               /* This can overflow a (size_t); check for this: */
-               tmp = buf_size;
-               tmp /= sprites[nsprites].width;
-               tmp /= sprites[nsprites].height;
-
-               if (tmp == sizeof (png_uint_16 [4]))
-               {
-                  sprites[nsprites].buffer = malloc(buf_size);
-                  /* This buffer must be initialized to transparent: */
-                  memset(sprites[nsprites].buffer, 0, buf_size);
-
-                  if (sprites[nsprites].buffer != NULL)
-                  {
-                     sprites[nsprites].file = NULL;
-                     ++argv, --argc;
-
-                     if (create_sprite(sprites+nsprites++, &argc, &argv))
-                     {
-                        result = 1; /* still ok */
-                        continue;
-                     }
-
-                     break; /* error */
-                  }
-               }
-
-               /* Overflow, or OOM */
-               fprintf(stderr, "simpleover: %s: sprite too large\n", argv[0]);
-               break;
-            }
-
-            else
-            {
-               fprintf(stderr, "simpleover: %s: invalid sprite (%u,%u)\n",
-                  argv[0], sprites[nsprites].width, sprites[nsprites].height);
-               break;
-            }
-         }
-
-         else
-         {
-            fprintf(stderr, "simpleover: %s: too many sprites\n", argv[0]);
-            break;
-         }
-      }
-
-      else if (strncmp(argv[0], "--add=", 6) == 0)
-      {
-         const char *name = argv[0]+6;
-         int isprite = nsprites;
-
-         ++argv, --argc;
-
-         while (--isprite >= 0)
-         {
-            if (strcmp(sprites[isprite].name, name) == 0)
-            {
-               if (!add_sprite(output, out_buf, sprites+isprite, &argc, &argv))
-                  goto out; /* error in add_sprite */
-
-               break;
-            }
-         }
-
-         if (isprite < 0) /* sprite not found */
-         {
-            fprintf(stderr, "simpleover: --add='%s': sprite not found\n", name);
-            break;
-         }
-      }
-
-      else
-      {
-         fprintf(stderr, "simpleover: %s: unrecognized operation\n", argv[0]);
-         break;
-      }
-
-      result = 1; /* ok  */
-   }
-
-   /* Clean up the cache of sprites: */
-out:
-   while (--nsprites >= 0)
-   {
-      if (sprites[nsprites].buffer != NULL)
-         free(sprites[nsprites].buffer);
-
-      if (sprites[nsprites].file != NULL)
-         (void)fclose(sprites[nsprites].file);
-   }
-
-   return result;
-}
-
-int main(int argc, const char **argv)
-{
-   int result = 1; /* default to fail */
-
-   if (argc >= 2)
-   {
-      int argi = 2;
-      const char *output = NULL;
-      png_image image;
-
-      if (argc > 2 && argv[2][0] != '-'/*an operation*/)
-      {
-         output = argv[2];
-         argi = 3;
-      }
-
-      image.version = PNG_IMAGE_VERSION;
-      image.opaque = NULL;
-
-      if (png_image_begin_read_from_file(&image, argv[1]))
-      {
-         png_bytep buffer;
-
-         image.format = PNG_FORMAT_RGB; /* 24-bit RGB */
-
-         buffer = malloc(PNG_IMAGE_SIZE(image));
-
-         if (buffer != NULL)
-         {
-            png_color background = {0, 0xff, 0}; /* fully saturated green */
-
-            if (png_image_finish_read(&image, &background, buffer,
-               0/*row_stride*/, NULL/*colormap for PNG_FORMAT_FLAG_COLORMAP */))
-            {
-               /* At this point png_image_finish_read has cleaned up the
-                * allocated data in png_image, and only the buffer needs to be
-                * freed.
-                *
-                * Perform the remaining operations:
-                */
-               if (simpleover_process(&image, buffer, argc-argi, argv+argi))
-               {
-                  /* Write the output: */
-                  if ((output != NULL &&
-                       png_image_write_to_file(&image, output,
-                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
-                        NULL/*colormap*/)) ||
-                      (output == NULL &&
-                       png_image_write_to_stdio(&image, stdout,
-                        0/*convert_to_8bit*/, buffer, 0/*row_stride*/,
-                        NULL/*colormap*/)))
-                     result = 0;
-
-                  else
-                     fprintf(stderr, "simpleover: write %s: %s\n",
-                        output == NULL ? "stdout" : output, image.message);
-               }
-
-               /* else simpleover_process writes an error message */
-            }
-
-            else
-               fprintf(stderr, "simpleover: read %s: %s\n", argv[1],
-                   image.message);
-
-            free(buffer);
-         }
-
-         else
-         {
-            fprintf(stderr, "simpleover: out of memory: %lu bytes\n",
-               (unsigned long)PNG_IMAGE_SIZE(image));
-
-            /* This is the only place where a 'free' is required; libpng does
-             * the cleanup on error and success, but in this case we couldn't
-             * complete the read because of running out of memory.
-             */
-            png_image_free(&image);
-         }
-      }
-
-      else
-      {
-         /* Failed to read the first argument: */
-         fprintf(stderr, "simpleover: %s: %s\n", argv[1], image.message);
-      }
-   }
-
-   else
-   {
-      /* Usage message */
-      fprintf(stderr,
-         "simpleover: usage: simpleover background.png [output.png]\n"
-         "  Output 'background.png' as a 24-bit RGB PNG file in 'output.png'\n"
-         "   or, if not given, stdout.  'background.png' will be composited\n"
-         "   on fully saturated green.\n"
-         "\n"
-         "  Optionally, before output, process additional PNG files:\n"
-         "\n"
-         "   --sprite=width,height,name {[--at=x,y] {sprite.png}}\n"
-         "    Produce a transparent sprite of size (width,height) and with\n"
-         "     name 'name'.\n"
-         "    For each sprite.png composite it using a Porter-Duff 'Over'\n"
-         "     operation at offset (x,y) in the sprite (defaulting to (0,0)).\n"
-         "     Input PNGs will be truncated to the area of the sprite.\n"
-         "\n"
-         "   --add='name' {x,y}\n"
-         "    Optionally, before output, composite a sprite, 'name', which\n"
-         "     must have been previously produced using --sprite, at each\n"
-         "     offset (x,y) in the output image.  Each sprite must fit\n"
-         "     completely within the output image.\n"
-         "\n"
-         "  PNG files are processed in the order they occur on the command\n"
-         "  line and thus the first PNG processed appears as the bottommost\n"
-         "  in the output image.\n");
-   }
-
-   return result;
-}
-#endif /* SIMPLIFIED_READ */
diff --git a/contrib/gregbook/COPYING b/contrib/gregbook/COPYING
deleted file mode 100644
index a3e9774..0000000
--- a/contrib/gregbook/COPYING
+++ /dev/null
@@ -1,340 +0,0 @@
-                    GNU GENERAL PUBLIC LICENSE
-                       Version 2, June 1991
-
- Copyright (C) 1989, 1991 Free Software Foundation, Inc.
-     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-                            Preamble
-
-  The licenses for most software are designed to take away your
-freedom to share and change it.  By contrast, the GNU General Public
-License is intended to guarantee your freedom to share and change free
-software--to make sure the software is free for all its users.  This
-General Public License applies to most of the Free Software
-Foundation's software and to any other program whose authors commit to
-using it.  (Some other Free Software Foundation software is covered by
-the GNU Library General Public License instead.)  You can apply it to
-your programs, too.
-
-  When we speak of free software, we are referring to freedom, not
-price.  Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-this service if you wish), that you receive source code or can get it
-if you want it, that you can change the software or use pieces of it
-in new free programs; and that you know you can do these things.
-
-  To protect your rights, we need to make restrictions that forbid
-anyone to deny you these rights or to ask you to surrender the rights.
-These restrictions translate to certain responsibilities for you if you
-distribute copies of the software, or if you modify it.
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-source code.  And you must show them these terms so they know their
-rights.
-
-  We protect your rights with two steps: (1) copyright the software, and
-(2) offer you this license which gives you legal permission to copy,
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-
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-that everyone understands that there is no warranty for this free
-software.  If the software is modified by someone else and passed on, we
-want its recipients to know that what they have is not the original, so
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-  Finally, any free program is threatened constantly by software
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-  The precise terms and conditions for copying, distribution and
-modification follow.
-
-                    GNU GENERAL PUBLIC LICENSE
-   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-
-  0. This License applies to any program or other work which contains
-a notice placed by the copyright holder saying it may be distributed
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-language.  (Hereinafter, translation is included without limitation in
-the term "modification".)  Each licensee is addressed as "you".
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-Activities other than copying, distribution and modification are not
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-running the Program is not restricted, and the output from the Program
-is covered only if its contents constitute a work based on the
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-You may charge a fee for the physical act of transferring a copy, and
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-
-These requirements apply to the modified work as a whole.  If
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-with the Program (or with a work based on the Program) on a volume of
-a storage or distribution medium does not bring the other work under
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-  3. You may copy and distribute the Program (or a work based on it,
-under Section 2) in object code or executable form under the terms of
-Sections 1 and 2 above provided that you also do one of the following:
-
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-
-  4. You may not copy, modify, sublicense, or distribute the Program
-except as expressly provided under this License.  Any attempt
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-void, and will automatically terminate your rights under this License.
-However, parties who have received copies, or rights, from you under
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-  5. You are not required to accept this License, since you have not
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-
-  6. Each time you redistribute the Program (or any work based on the
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-You are not responsible for enforcing compliance by third parties to
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-  7. If, as a consequence of a court judgment or allegation of patent
-infringement or for any other reason (not limited to patent issues),
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-license would not permit royalty-free redistribution of the Program by
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-the only way you could satisfy both it and this License would be to
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-If any portion of this section is held invalid or unenforceable under
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-such claims; this section has the sole purpose of protecting the
-integrity of the free software distribution system, which is
-implemented by public license practices.  Many people have made
-generous contributions to the wide range of software distributed
-through that system in reliance on consistent application of that
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-to distribute software through any other system and a licensee cannot
-impose that choice.
-
-This section is intended to make thoroughly clear what is believed to
-be a consequence of the rest of this License.
-
-  8. If the distribution and/or use of the Program is restricted in
-certain countries either by patents or by copyrighted interfaces, the
-original copyright holder who places the Program under this License
-may add an explicit geographical distribution limitation excluding
-those countries, so that distribution is permitted only in or among
-countries not thus excluded.  In such case, this License incorporates
-the limitation as if written in the body of this License.
-
-  9. The Free Software Foundation may publish revised and/or new versions
-of the General Public License from time to time.  Such new versions will
-be similar in spirit to the present version, but may differ in detail to
-address new problems or concerns.
-
-Each version is given a distinguishing version number.  If the Program
-specifies a version number of this License which applies to it and "any
-later version", you have the option of following the terms and conditions
-either of that version or of any later version published by the Free
-Software Foundation.  If the Program does not specify a version number of
-this License, you may choose any version ever published by the Free Software
-Foundation.
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-  10. If you wish to incorporate parts of the Program into other free
-programs whose distribution conditions are different, write to the author
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-make exceptions for this.  Our decision will be guided by the two goals
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-of promoting the sharing and reuse of software generally.
-
-                            NO WARRANTY
-
-  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
-FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
-OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
-PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
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-PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
-REPAIR OR CORRECTION.
-
-  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
-REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
-INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
-OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
-TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
-YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
-PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGES.
-
-                     END OF TERMS AND CONDITIONS
-
-            How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
-convey the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-
-Also add information on how to contact you by electronic and paper mail.
-
-If the program is interactive, make it output a short notice like this
-when it starts in an interactive mode:
-
-    Gnomovision version 69, Copyright (C) year  name of author
-    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
-    This is free software, and you are welcome to redistribute it
-    under certain conditions; type `show c' for details.
-
-The hypothetical commands `show w' and `show c' should show the appropriate
-parts of the General Public License.  Of course, the commands you use may
-be called something other than `show w' and `show c'; they could even be
-mouse-clicks or menu items--whatever suits your program.
-
-You should also get your employer (if you work as a programmer) or your
-school, if any, to sign a "copyright disclaimer" for the program, if
-necessary.  Here is a sample; alter the names:
-
-  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
-  `Gnomovision' (which makes passes at compilers) written by James Hacker.
-
-  <signature of Ty Coon>, 1 April 1989
-  Ty Coon, President of Vice
-
-This General Public License does not permit incorporating your program into
-proprietary programs.  If your program is a subroutine library, you may
-consider it more useful to permit linking proprietary applications with the
-library.  If this is what you want to do, use the GNU Library General
-Public License instead of this License.
diff --git a/contrib/gregbook/LICENSE b/contrib/gregbook/LICENSE
deleted file mode 100644
index d956717..0000000
--- a/contrib/gregbook/LICENSE
+++ /dev/null
@@ -1,50 +0,0 @@
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------
diff --git a/contrib/gregbook/Makefile.mingw32 b/contrib/gregbook/Makefile.mingw32
deleted file mode 100644
index 3a3ff60..0000000
--- a/contrib/gregbook/Makefile.mingw32
+++ /dev/null
@@ -1,131 +0,0 @@
-# Sample makefile for rpng-win / rpng2-win / wpng using mingw32-gcc and make.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a DOS-prompt window via:
-#
-#	make -f Makefile.mingw32
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are in subdirectories at the same level as the current subdirectory
-# (as indicated by the PNGDIR and ZDIR macros below).  It makes no assumptions
-# at all about the mingw32 installation tree (W32DIR).  Edit as appropriate.
-#
-# Note that the names of the dynamic and static libpng and zlib libraries
-# used below may change in later releases of the libraries.  This makefile
-# builds both statically and dynamically linked executables by default.
-# (You need only one set, but for testing it can be handy to have both.)
-
-
-# macros --------------------------------------------------------------------
-
-#PNGDIR = ../..#		for libpng-x.y.z/contrib/gregbook builds
-PNGDIR = ../libpng-win32
-PNGINC = -I$(PNGDIR)
-PNGLIBd = $(PNGDIR)/libpng.dll.a	# dynamically linked
-PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
-
-#ZDIR = ../../../zlib-win32#	for libpng-x.y.z/contrib/gregbook builds
-ZDIR = ../zlib-win32
-ZINC = -I$(ZDIR)
-ZLIBd = $(ZDIR)/libzdll.a
-ZLIBs = $(ZDIR)/libz.a
-
-# change this to be the path where mingw32 installs its stuff:
-W32DIR =
-#W32DIR = /usr/local/cross-tools/i386-mingw32msvc
-W32INC = -I$(W32DIR)/include
-W32LIB = $(W32DIR)/lib/libuser32.a $(W32DIR)/lib/libgdi32.a
-
-CC = gcc
-#CC = i386-mingw32msvc-gcc #	e.g., Linux -> Win32 cross-compilation
-LD = $(CC)
-RM = rm -f
-CPPFLAGS = $(INCS)
-CFLAGS = -O -Wall $(MINGW_CCFLAGS)
-# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic and -W can also be used]
-LDFLAGS = $(MINGW_LDFLAGS)
-O = .o
-E = .exe
-
-INCS = $(PNGINC) $(ZINC) $(W32INC)
-RLIBSd = $(PNGLIBd) $(ZLIBd) $(W32LIB) -lm
-RLIBSs = $(PNGLIBs) $(ZLIBs) $(W32LIB) -lm
-WLIBSd = $(PNGLIBd) $(ZLIBd)
-WLIBSs = $(PNGLIBs) $(ZLIBs)
-
-RPNG   = rpng-win
-RPNG2  = rpng2-win
-WPNG   = wpng
-
-ROBJSd  = $(RPNG)$(O) readpng.pic$(O)
-ROBJS2d = $(RPNG2)$(O) readpng2.pic$(O)
-WOBJSd  = $(WPNG)$(O) writepng.pic$(O)
-
-RPNGs  = $(RPNG)-static
-RPNG2s = $(RPNG2)-static
-WPNGs  = $(WPNG)-static
-
-ROBJSs  = $(RPNG)$(O) readpng$(O)
-ROBJS2s = $(RPNG2)$(O) readpng2$(O)
-WOBJSs  = $(WPNG)$(O) writepng$(O)
-
-STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
-DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
-
-%.pic$(O): %.c
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) -DPNG_BUILD_DLL -o $@ $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNGs)$(E): $(ROBJSs)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJSs) $(RLIBSs)
-
-$(RPNG)$(E): $(ROBJSd)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJSd) $(RLIBSd)
-
-$(RPNG2s)$(E): $(ROBJS2s)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2s) $(RLIBSs)
-
-$(RPNG2)$(E): $(ROBJS2d)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2d) $(RLIBSd)
-
-$(WPNGs)$(E): $(WOBJSs)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJSs) $(WLIBSs)
-
-$(WPNG)$(E): $(WOBJSd)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJSd) $(WLIBSd)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O) readpng.pic$(O):	readpng.c readpng.h
-readpng2$(O) readpng2.pic$(O):	readpng2.c readpng2.h
-writepng$(O) writepng.pic$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES)
-	$(RM) $(ROBJSs) $(ROBJS2s) $(WOBJSs)
-	$(RM) $(ROBJSd) $(ROBJS2d) $(WOBJSd)
diff --git a/contrib/gregbook/Makefile.sgi b/contrib/gregbook/Makefile.sgi
deleted file mode 100644
index 94d61b4..0000000
--- a/contrib/gregbook/Makefile.sgi
+++ /dev/null
@@ -1,105 +0,0 @@
-# Sample makefile for rpng-x / rpng2-x / wpng for SGI using cc and make.
-# Greg Roelofs
-# Last modified:  7 March 2002
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Buy some for friends
-#	and family, too.  (Not that this is a blatant plug or anything.)
-#
-# Invoke this makefile from a shell prompt in the usual way; for example:
-#
-#	make -f Makefile.sgi
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are both installed in /usr/local/{include,lib} (as indicated by the
-# PNG* and Z* macros below).  Edit as appropriate--choose only ONE each of
-# the PNGINC, PNGLIB, ZINC and ZLIB lines.
-#
-# This makefile builds dynamically linked executables (against libpng and zlib,
-# that is), but that can be changed by uncommenting the appropriate PNGLIB and
-# ZLIB lines.
-
-
-# macros --------------------------------------------------------------------
-
-PNGINC = -I/usr/local/include/libpng16
-PNGLIB = -L/usr/local/lib -lpng16	  # dynamically linked against libpng
-#PNGLIB = /usr/local/lib/libpng16.a # statically linked against libpng
-# or:
-#PNGINC = -I../..
-#PNGLIB = -L../.. -lpng
-#PNGLIB = ../../libpng.a
-
-ZINC = -I/usr/local/include
-ZLIB = -L/usr/local/lib -lz		# dynamically linked against zlib
-#ZLIB = /usr/local/lib/libz.a		# statically linked against zlib
-#ZINC = -I../zlib
-#ZLIB = -L../zlib -lz
-#ZLIB = ../../../zlib/libz.a
-
-XINC = -I/usr/include/X11		# old-style, stock X distributions
-XLIB = -L/usr/lib/X11 -lX11
-#XINC = -I/usr/openwin/include    	# Sun workstations (OpenWindows)
-#XLIB = -L/usr/openwin/lib -lX11
-#XINC = -I/usr/X11R6/include		# new X distributions (XFree86, etc.)
-#XLIB = -L/usr/X11R6/lib -lX11
-
-INCS = $(PNGINC) $(ZINC) $(XINC)
-RLIBS = $(PNGLIB) $(ZLIB) $(XLIB) -lm
-WLIBS = $(PNGLIB) $(ZLIB)
-
-CC = cc
-LD = cc
-RM = rm -f
-# ABI must be the same as that used to build libpng.
-ABI =
-CPPFLAGS =
-CFLAGS = $(ABI) -O -fullwarn $(INCS)
-LDFLAGS = $(ABI)
-O = .o
-E =
-
-RPNG  = rpng-x
-RPNG2 = rpng2-x
-WPNG  = wpng
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBS)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBS)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBS)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/contrib/gregbook/Makefile.unx b/contrib/gregbook/Makefile.unx
deleted file mode 100644
index 1a73e03..0000000
--- a/contrib/gregbook/Makefile.unx
+++ /dev/null
@@ -1,134 +0,0 @@
-# Sample makefile for rpng-x / rpng2-x / wpng using gcc and make.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a shell prompt in the usual way; for example:
-#
-#	make -f Makefile.unx
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are installed in /usr/local/{include,lib} or as otherwise indicated by
-# the PNG* and Z* macros below.  Edit as appropriate--choose only ONE each of
-# the PNGINC, PNGLIBd, PNGLIBs, ZINC, ZLIBd and ZLIBs lines.
-#
-# This makefile builds both dynamically and statically linked executables
-# (against libpng and zlib, that is), but that can be changed by modifying
-# the "EXES =" line.  (You need only one set, but for testing it can be handy
-# to have both.)
-
-
-# macros --------------------------------------------------------------------
-
-#PNGDIR = /usr/local/lib
-#PNGINC = -I/usr/local/include/libpng16
-#PNGLIBd = -L$(PNGDIR) -lpng16 # dynamically linked, installed libpng
-#PNGLIBs = $(PNGDIR)/libpng16.a # statically linked, installed libpng
-# or:
-PNGDIR = ../..#	this one is for libpng-x.y.z/contrib/gregbook builds
-#PNGDIR = ../libpng
-PNGINC = -I$(PNGDIR)
-PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng16	# dynamically linked
-PNGLIBs = $(PNGDIR)/libpng.a		# statically linked, local libpng
-
-ZDIR = /usr/local/lib
-#ZDIR = /usr/lib64
-ZINC = -I/usr/local/include
-ZLIBd = -L$(ZDIR) -lz			# dynamically linked against zlib
-ZLIBs = $(ZDIR)/libz.a			# statically linked against zlib
-# or:
-#ZDIR = ../zlib
-#ZINC = -I$(ZDIR)
-#ZLIBd = -Wl,-rpath,$(ZDIR) -L$(ZDIR) -lz  # -rpath allows in-place testing
-#ZLIBs = $(ZDIR)/libz.a
-
-#XINC = -I/usr/include			# old-style, stock X distributions
-#XLIB = -L/usr/lib/X11 -lX11		#  (including SGI IRIX)
-#XINC = -I/usr/openwin/include		# Sun workstations (OpenWindows)
-#XLIB = -L/usr/openwin/lib -lX11
-XINC = -I/usr/X11R6/include		# new X distributions (X.org, etc.)
-XLIB = -L/usr/X11R6/lib -lX11
-#XLIB = -L/usr/X11R6/lib64 -lX11	# e.g., Red Hat on AMD64
-
-INCS = $(PNGINC) $(ZINC) $(XINC)
-RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
-RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
-WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
-WLIBSs = $(PNGLIBs) $(ZLIBs) -lm
-
-CC = gcc
-LD = gcc
-RM = rm -f
-CPPFLAGS = $(INCS) -DFEATURE_LOOP
-CFLAGS = -O -Wall
-#CFLAGS = -O -W -Wall -Wextra -pedantic -ansi
-# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
-# [-ansi, -pedantic, -Wextra, and -W can also be used]
-LDFLAGS =
-O = .o
-E =
-
-RPNG   = rpng-x
-RPNG2  = rpng2-x
-WPNG   = wpng
-
-RPNGs  = $(RPNG)-static
-RPNG2s = $(RPNG2)-static
-WPNGs  = $(WPNG)-static
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
-DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNGs)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSs)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSd)
-
-$(RPNG2s)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSs)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSd)
-
-$(WPNGs)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSs)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSd)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/contrib/gregbook/Makefile.w32 b/contrib/gregbook/Makefile.w32
deleted file mode 100644
index ab7dcf7..0000000
--- a/contrib/gregbook/Makefile.w32
+++ /dev/null
@@ -1,114 +0,0 @@
-# Sample makefile for rpng-win / rpng2-win / wpng using MSVC and NMAKE.
-# Greg Roelofs
-# Last modified:  2 June 2007
-#
-#	The programs built by this makefile are described in the book,
-#	"PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
-#	Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
-#	generally for sale anymore, but it's the thought that counts,
-#	right?  (Hint:  http://www.libpng.org/pub/png/book/ )
-#
-# Invoke this makefile from a DOS prompt window via:
-#
-#	%devstudio%\vc\bin\vcvars32.bat
-#	nmake -nologo -f Makefile.w32
-#
-# where %devstudio% is the installation directory for MSVC / DevStudio.  If
-# you get "environment out of space" errors, create a desktop shortcut with
-# "c:\windows\command.com /e:4096" as the program command line and set the
-# working directory to this directory.  Then double-click to open the new
-# DOS-prompt window with a bigger environment and retry the commands above.
-#
-# This makefile assumes libpng and zlib have already been built or downloaded
-# and are in subdirectories at the same level as the current subdirectory
-# (as indicated by the PNGPATH and ZPATH macros below).  Edit as appropriate.
-#
-# Note that the names of the dynamic and static libpng and zlib libraries
-# used below may change in later releases of the libraries.  This makefile
-# builds statically linked executables, but that can be changed by uncom-
-# menting the appropriate PNGLIB and ZLIB lines.
-
-!include <ntwin32.mak>
-
-
-# macros --------------------------------------------------------------------
-
-PNGPATH = ../libpng
-PNGINC = -I$(PNGPATH)
-#PNGLIB = $(PNGPATH)/pngdll.lib
-PNGLIB = $(PNGPATH)/libpng.lib
-
-ZPATH = ../zlib
-ZINC = -I$(ZPATH)
-#ZLIB = $(ZPATH)/zlibdll.lib
-ZLIB = $(ZPATH)/zlibstat.lib
-
-WINLIBS = -defaultlib:user32.lib gdi32.lib
-# ["real" apps may also need comctl32.lib, comdlg32.lib, winmm.lib, etc.]
-
-INCS = $(PNGINC) $(ZINC)
-RLIBS = $(PNGLIB) $(ZLIB) $(WINLIBS)
-WLIBS = $(PNGLIB) $(ZLIB)
-
-CC = cl
-LD = link
-RM = del
-CPPFLAGS = $(INCS)
-CFLAGS = -nologo -O -W3 $(cvars)
-# [note that -W3 is an MSVC-specific compilation flag ("all warnings on")]
-# [see %devstudio%\vc\include\win32.mak for cvars macro definition]
-O = .obj
-E = .exe
-
-RLDFLAGS = -nologo -subsystem:windows
-WLDFLAGS = -nologo
-
-RPNG  = rpng-win
-RPNG2 = rpng2-win
-WPNG  = wpng
-
-ROBJS  = $(RPNG)$(O) readpng$(O)
-ROBJS2 = $(RPNG2)$(O) readpng2$(O)
-WOBJS  = $(WPNG)$(O) writepng$(O)
-
-EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
-
-
-# implicit make rules -------------------------------------------------------
-
-.c$(O):
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $<
-
-
-# dependencies --------------------------------------------------------------
-
-all:  $(EXES)
-
-$(RPNG)$(E): $(ROBJS)
-	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS) $(RLIBS)
-
-$(RPNG2)$(E): $(ROBJS2)
-	$(LD) $(RLDFLAGS) -out:$@ $(ROBJS2) $(RLIBS)
-
-$(WPNG)$(E): $(WOBJS)
-	$(LD) $(WLDFLAGS) -out:$@ $(WOBJS) $(WLIBS)
-
-$(RPNG)$(O):	$(RPNG).c readpng.h
-$(RPNG2)$(O):	$(RPNG2).c readpng2.h
-$(WPNG)$(O):	$(WPNG).c writepng.h
-
-readpng$(O):	readpng.c readpng.h
-readpng2$(O):	readpng2.c readpng2.h
-writepng$(O):	writepng.c writepng.h
-
-
-# maintenance ---------------------------------------------------------------
-
-clean:
-#	ideally we could just do this:
-#	$(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
-#	...but the Windows "DEL" command is none too bright, so:
-	$(RM) r*$(E)
-	$(RM) w*$(E)
-	$(RM) r*$(O)
-	$(RM) w*$(O)
diff --git a/contrib/gregbook/README b/contrib/gregbook/README
deleted file mode 100644
index 7b1f6a3..0000000
--- a/contrib/gregbook/README
+++ /dev/null
@@ -1,186 +0,0 @@
-                     ===========================
-                      PNG: The Definitive Guide
-                     ===========================
-
-                             Source Code
-
-Chapters 13, 14 and 15 of "PNG: The Definitive Guide" discuss three free,
-cross-platform demo programs that show how to use the libpng reference
-library:  rpng, rpng2 and wpng.  rpng and rpng2 are viewers; the first is
-a very simple example that that shows how a standard file-viewer might use
-libpng, while the second is designed to process streaming data and shows
-how a web browser might be written.  wpng is a simple command-line program
-that reads binary PGM and PPM files (the ``raw'' grayscale and RGB subsets
-of PBMPLUS/NetPBM) and converts them to PNG.
-
-The source code for all three demo programs currently compiles under
-Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
-zinser@decus.de, for making the necessary changes for OpenVMS and for
-providing an appropriate build script.)  Build instructions can be found
-below.
-
-Files:
-
-   README             this file
-   LICENSE            terms of distribution and reuse (BSD-like or GNU GPL)
-   COPYING            GNU General Public License (GPL)
-
-   Makefile.unx       Unix makefile
-   Makefile.w32       Windows (MSVC) makefile
-   makevms.com        OpenVMS build script
-
-   rpng-win.c         Windows front end for the basic viewer
-   rpng-x.c           X Window System (Unix, OpenVMS) front end
-   readpng.c          generic back end for the basic viewer
-   readpng.h          header file for the basic viewer
-
-   rpng2-win.c        Windows front end for the progressive viewer
-   rpng2-x.c          X front end for the progressive viewer
-   readpng2.c         generic back end for the progressive viewer
-   readpng2.h         header file for the progressive viewer
-
-   wpng.c             generic (text) front end for the converter
-   writepng.c         generic back end for the converter
-   writepng.h         header file for the converter
-
-   toucan.png         transparent PNG for testing (by Stefan Schneider)
-
-Note that, although the programs are designed to be functional, their
-primary purpose is to illustrate how to use libpng to add PNG support to
-other programs.  As such, their user interfaces are crude and definitely
-are not intended for everyday use.
-
-Please see http://www.libpng.org/pub/png/pngbook.html for further infor-
-mation and links to the latest version of the source code, and Chapters
-13-15 of the book for detailed discussion of the three programs.
-
-Greg Roelofs
-http://pobox.com/~newt/greg_contact.html
-16 March 2008
-
-
-BUILD INSTRUCTIONS
-
- - Prerequisites (in order of compilation):
-
-      - zlib            http://zlib.net/
-      - libpng          http://www.libpng.org/pub/png/libpng.html
-      - pngbook         http://www.libpng.org/pub/png/book/sources.html
-
-     The pngbook demo programs are explicitly designed to demonstrate proper
-     coding techniques for using the libpng reference library.  As a result,
-     you need to download and build both zlib (on which libpng depends) and
-     libpng.  A common build setup is to place the zlib, libpng and pngbook
-     subdirectory trees ("folders") in the same parent directory.  Then the
-     libpng build can refer to files in ../zlib (or ..\zlib or [-.zlib]),
-     and similarly for the pngbook build.
-
-     Note that all three packages are designed to be built from a command
-     line by default; those who wish to use a graphical or other integrated
-     development environments are on their own.
-
-
- - Unix:
-
-     Unpack the latest pngbook sources (which should correspond to this
-     README file) into a directory and change into that directory.
-
-     Copy Makefile.unx to Makefile and edit the PNG* and Z* variables
-     appropriately (possibly also the X* variables if necessary).
-
-     make
-
-     There is no "install" target, so copy the three executables somewhere
-     in your path or run them from the current directory.  All three will
-     print a basic usage screen when run without any command-line arguments;
-     see the book for more details.
-
-
- - Windows:
-
-     Unpack the latest pngbook sources (which should correspond to this
-     README file) into a folder, open a "DOS shell" or "command prompt"
-     or equivalent command-line window, and cd into the folder where you
-     unpacked the source code.
-
-     For MSVC, set up the necessary environment variables by invoking
-
-        %devstudio%\vc\bin\vcvars32.bat
-
-     where where %devstudio% is the installation directory for MSVC /
-     DevStudio.  If you get "environment out of space" errors under 95/98,
-     create a desktop shortcut with "c:\windows\command.com /e:4096" as
-     the program command line and set the working directory to the pngbook
-     directory.  Then double-click to open the new DOS-prompt window with
-     a bigger environment and retry the commands above.
-
-     Copy Makefile.w32 to Makefile and edit the PNGPATH and ZPATH variables
-     appropriately (possibly also the "INC" and "LIB" variables if needed).
-     Note that the names of the dynamic and static libpng and zlib libraries
-     used in the makefile may change in later releases of the libraries.
-     Also note that, as of libpng version 1.0.5, MSVC DLL builds do not work.
-     This makefile therefore builds statically linked executables, but if
-     the DLL problems ever get fixed, uncommenting the appropriate PNGLIB
-     and ZLIB lines will build dynamically linked executables instead.
-
-     Do the build by typing
-
-        nmake
-
-     The result should be three executables:  rpng-win.exe, rpng2-win.exe,
-     and wpng.exe.  Copy them somewhere in your PATH or run them from the
-     current folder.  Like the Unix versions, the two windowed programs
-     (rpng and rpng2) now display a usage screen in a console window when
-     invoked without command-line arguments; this is new behavior as of
-     the June 2001 release.  Note that the programs use the Unix-style "-"
-     character to specify options, instead of the more common DOS/Windows
-     "/" character.  (For example:  "rpng2-win -bgpat 4 foo.png", not
-     "rpng2-win /bgpat 4 foo.png")
-
-
- - OpenVMS:
-
-     Unpack the pngbook sources into a subdirectory and change into that
-     subdirectory.
-
-     Edit makevms.com appropriately, specifically the zpath and pngpath
-     variables.
-
-     @makevms
-
-     To run the programs, they probably first need to be set up as "foreign
-     symbols," with "disk" and "dir" set appropriately:
-
-     $ rpng  == "$disk:[dir]rpng-x.exe"
-     $ rpng2 == "$disk:[dir]rpng2-x.exe"
-     $ wpng  == "$disk:[dir]wpng.exe"
-
-     All three will print a basic usage screen when run without any command-
-     line arguments; see the book for more details.  Note that the options
-     style is Unix-like, i.e., preceded by "-" rather than "/".
-
-
-RUNNING THE PROGRAMS:  (VERY) BRIEF INTRO
-
-     rpng is a simple PNG viewer that can display transparent PNGs with a
-     specified background color; for example,
-
-        rpng -bgcolor \#ff0000 toucan.png
-
-     would display the image with a red background.  rpng2 is a progressive
-     viewer that simulates a web browser in some respects; it can display
-     images against either a background color or a dynamically generated
-     background image.  For example:
-
-        rpng2 -bgpat 16 toucan.png
-
-     wpng is a purely command-line image converter from binary PBMPLUS/NetPBM
-     format (.pgm or .ppm) to PNG; for example,
-
-        wpng -time < toucan-notrans.ppm > toucan-notrans.png
-
-     would convert the specified PPM file (using redirection) to PNG, auto-
-     matically setting the PNG modification-time chunk.
-
-     All options can be abbreviated to the shortest unique value; for example,
-     "-bgc" for -bgcolor (versus "-bgp" for -bgpat), or "-g" for -gamma.
diff --git a/contrib/gregbook/makevms.com b/contrib/gregbook/makevms.com
deleted file mode 100644
index f32bcab..0000000
--- a/contrib/gregbook/makevms.com
+++ /dev/null
@@ -1,132 +0,0 @@
-$!------------------------------------------------------------------------------
-$! make "PNG: The Definitive Guide" demo programs (for X) under OpenVMS
-$!
-$! Script created by Martin Zinser for libpng; modified by Greg Roelofs
-$! for standalone pngbook source distribution.
-$!
-$!
-$!    Set locations where zlib and libpng sources live.
-$!
-$ zpath   = ""
-$ pngpath = ""
-$!
-$ if f$search("[---.zlib]zlib.h").nes."" then zpath = "[---.zlib]"
-$ if f$search("[--]png.h").nes."" then pngpath = "[--]"
-$!
-$ if f$search("[-.zlib]zlib.h").nes."" then zpath = "[-.zlib]"
-$ if f$search("[-.libpng]png.h").nes."" then pngpath = "[-.libpng]"
-$!
-$ if zpath .eqs. ""
-$ then
-$   write sys$output "zlib include not found. Exiting..."
-$   exit 2
-$ endif
-$!
-$ if pngpath .eqs. ""
-$ then
-$   write sys$output "libpng include not found. Exiting..."
-$   exit 2
-$ endif
-$!
-$!    Look for the compiler used.
-$!
-$ ccopt="/include=(''zpath',''pngpath')"
-$ if f$getsyi("HW_MODEL").ge.1024
-$ then
-$  ccopt = "/prefix=all"+ccopt
-$  comp  = "__decc__=1"
-$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$ else
-$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
-$   then
-$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
-$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
-$     then
-$      comp  = "__gcc__=1"
-$      CC :== GCC
-$     else
-$      comp = "__vaxc__=1"
-$     endif
-$   else
-$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
-$    ccopt = "/decc/prefix=all"+ccopt
-$    comp  = "__decc__=1"
-$  endif
-$ endif
-$ open/write lopt lib.opt
-$ write lopt "''pngpath'libpng.olb/lib"
-$ write lopt "''zpath'libz.olb/lib"
-$ close lopt
-$ open/write xopt x11.opt
-$ write xopt "sys$library:decw$xlibshr.exe/share"
-$ close xopt
-$!
-$!    Build 'em.
-$!
-$ write sys$output "Compiling PNG book programs ..."
-$   CALL MAKE readpng.OBJ "cc ''CCOPT' readpng" -
-	readpng.c readpng.h
-$   CALL MAKE readpng2.OBJ "cc ''CCOPT' readpng2" -
-	readpng2.c readpng2.h
-$   CALL MAKE writepng.OBJ "cc ''CCOPT' writepng" -
-	writepng.c writepng.h
-$   write sys$output "Building rpng-x..."
-$   CALL MAKE rpng-x.OBJ "cc ''CCOPT' rpng-x" -
-	rpng-x.c readpng.h
-$   call make rpng-x.exe -
-	"LINK rpng-x,readpng,lib.opt/opt,x11.opt/opt" -
-	rpng-x.obj readpng.obj
-$   write sys$output "Building rpng2-x..."
-$   CALL MAKE rpng2-x.OBJ "cc ''CCOPT' rpng2-x" -
-	rpng2-x.c readpng2.h
-$   call make rpng2-x.exe -
-	"LINK rpng2-x,readpng2,lib.opt/opt,x11.opt/opt" -
-	rpng2-x.obj readpng2.obj
-$   write sys$output "Building wpng..."
-$   CALL MAKE wpng.OBJ "cc ''CCOPT' wpng" -
-	wpng.c writepng.h
-$   call make wpng.exe -
-	"LINK wpng,writepng,lib.opt/opt" -
-	wpng.obj writepng.obj
-$ exit
-$!
-$!
-$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
-$ V = 'F$Verify(0)
-$! P1 = What we are trying to make
-$! P2 = Command to make it
-$! P3 - P8  What it depends on
-$
-$ If F$Search(P1) .Eqs. "" Then Goto Makeit
-$ Time = F$CvTime(F$File(P1,"RDT"))
-$arg=3
-$Loop:
-$       Argument = P'arg
-$       If Argument .Eqs. "" Then Goto Exit
-$       El=0
-$Loop2:
-$       File = F$Element(El," ",Argument)
-$       If File .Eqs. " " Then Goto Endl
-$       AFile = ""
-$Loop3:
-$       OFile = AFile
-$       AFile = F$Search(File)
-$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
-$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
-$       Goto Loop3
-$NextEL:
-$       El = El + 1
-$       Goto Loop2
-$EndL:
-$ arg=arg+1
-$ If arg .Le. 8 Then Goto Loop
-$ Goto Exit
-$
-$Makeit:
-$ VV=F$VERIFY(0)
-$ write sys$output P2
-$ 'P2
-$ VV='F$Verify(VV)
-$Exit:
-$ If V Then Set Verify
-$ENDSUBROUTINE
diff --git a/contrib/gregbook/readpng.c b/contrib/gregbook/readpng.c
deleted file mode 100644
index 9167403..0000000
--- a/contrib/gregbook/readpng.c
+++ /dev/null
@@ -1,317 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readpng.c
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <zlib.h>
-
-#include "png.h"        /* libpng header */
-#include "readpng.h"    /* typedefs, common macros, public prototypes */
-
-/* future versions of libpng will provide this macro: */
-#ifndef png_jmpbuf
-#  define png_jmpbuf(png_ptr)   ((png_ptr)->jmpbuf)
-#endif
-
-
-static png_structp png_ptr = NULL;
-static png_infop info_ptr = NULL;
-
-png_uint_32  width, height;
-int  bit_depth, color_type;
-uch  *image_data = NULL;
-
-
-void readpng_version_info(void)
-{
-    fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
-      PNG_LIBPNG_VER_STRING, png_libpng_ver);
-    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
-      ZLIB_VERSION, zlib_version);
-}
-
-
-/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
-{
-    uch sig[8];
-
-
-    /* first do a quick check that the file really is a PNG image; could
-     * have used slightly more general png_sig_cmp() function instead */
-
-    fread(sig, 1, 8, infile);
-    if (png_sig_cmp(sig, 0, 8))
-        return 1;   /* bad signature */
-
-
-    /* could pass pointers to user-defined error handlers instead of NULLs: */
-
-    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), NULL, NULL,
-        NULL);
-    if (!png_ptr)
-        return 4;   /* out of memory */
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        png_destroy_read_struct(&png_ptr, NULL, NULL);
-        return 4;   /* out of memory */
-    }
-
-
-    /* we could create a second info struct here (end_info), but it's only
-     * useful if we want to keep pre- and post-IDAT chunk info separated
-     * (mainly for PNG-aware image editors and converters) */
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-    png_init_io(png_ptr, infile);
-    png_set_sig_bytes(png_ptr, 8);  /* we already read the 8 signature bytes */
-
-    png_read_info(png_ptr, info_ptr);  /* read all PNG info up to image data */
-
-
-    /* alternatively, could make separate calls to png_get_image_width(),
-     * etc., but want bit_depth and color_type for later [don't care about
-     * compression_type and filter_type => NULLs] */
-
-    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
-      NULL, NULL, NULL);
-    *pWidth = width;
-    *pHeight = height;
-
-
-    /* OK, that's all we need for now; return happy */
-
-    return 0;
-}
-
-
-
-
-/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
- * scales values to 8-bit if necessary */
-
-int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
-{
-    png_color_16p pBackground;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-    if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
-        return 1;
-
-    /* it is not obvious from the libpng documentation, but this function
-     * takes a pointer to a pointer, and it always returns valid red, green
-     * and blue values, regardless of color_type: */
-
-    png_get_bKGD(png_ptr, info_ptr, &pBackground);
-
-
-    /* however, it always returns the raw bKGD data, regardless of any
-     * bit-depth transformations, so check depth and adjust if necessary */
-
-    if (bit_depth == 16) {
-        *red   = pBackground->red   >> 8;
-        *green = pBackground->green >> 8;
-        *blue  = pBackground->blue  >> 8;
-    } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
-        if (bit_depth == 1)
-            *red = *green = *blue = pBackground->gray? 255 : 0;
-        else if (bit_depth == 2)
-            *red = *green = *blue = (255/3) * pBackground->gray;
-        else /* bit_depth == 4 */
-            *red = *green = *blue = (255/15) * pBackground->gray;
-    } else {
-        *red   = (uch)pBackground->red;
-        *green = (uch)pBackground->green;
-        *blue  = (uch)pBackground->blue;
-    }
-
-    return 0;
-}
-
-
-
-
-/* display_exponent == LUT_exponent * CRT_exponent */
-
-uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
-{
-    double  gamma;
-    png_uint_32  i, rowbytes;
-    png_bytepp  row_pointers = NULL;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        free(image_data);
-        image_data = NULL;
-        free(row_pointers);
-        row_pointers = NULL;
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return NULL;
-    }
-
-
-    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
-     * transparency chunks to full alpha channel; strip 16-bit-per-sample
-     * images to 8 bits per sample; and convert grayscale to RGB[A] */
-
-    if (color_type == PNG_COLOR_TYPE_PALETTE)
-        png_set_expand(png_ptr);
-    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
-        png_set_expand(png_ptr);
-    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-        png_set_expand(png_ptr);
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-    if (bit_depth == 16)
-#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-        png_set_scale_16(png_ptr);
-#  else
-        png_set_strip_16(png_ptr);
-#  endif
-#endif
-    if (color_type == PNG_COLOR_TYPE_GRAY ||
-        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-        png_set_gray_to_rgb(png_ptr);
-
-
-    /* unlike the example in the libpng documentation, we have *no* idea where
-     * this file may have come from--so if it doesn't have a file gamma, don't
-     * do any correction ("do no harm") */
-
-    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
-        png_set_gamma(png_ptr, display_exponent, gamma);
-
-
-    /* all transformations have been registered; now update info_ptr data,
-     * get rowbytes and channels, and allocate image memory */
-
-    png_read_update_info(png_ptr, info_ptr);
-
-    *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
-    *pChannels = (int)png_get_channels(png_ptr, info_ptr);
-
-    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return NULL;
-    }
-    if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        free(image_data);
-        image_data = NULL;
-        return NULL;
-    }
-
-    Trace((stderr, "readpng_get_image:  channels = %d, rowbytes = %ld, height = %ld\n",
-        *pChannels, rowbytes, height));
-
-
-    /* set the individual row_pointers to point at the correct offsets */
-
-    for (i = 0;  i < height;  ++i)
-        row_pointers[i] = image_data + i*rowbytes;
-
-
-    /* now we can go ahead and just read the whole image */
-
-    png_read_image(png_ptr, row_pointers);
-
-
-    /* and we're done!  (png_read_end() can be omitted if no processing of
-     * post-IDAT text/time/etc. is desired) */
-
-    free(row_pointers);
-    row_pointers = NULL;
-
-    png_read_end(png_ptr, NULL);
-
-    return image_data;
-}
-
-
-void readpng_cleanup(int free_image_data)
-{
-    if (free_image_data && image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-
-    if (png_ptr && info_ptr) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        png_ptr = NULL;
-        info_ptr = NULL;
-    }
-}
diff --git a/contrib/gregbook/readpng.h b/contrib/gregbook/readpng.h
deleted file mode 100644
index fad9fe3..0000000
--- a/contrib/gregbook/readpng.h
+++ /dev/null
@@ -1,88 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readpng.h
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#ifndef TRUE
-#  define TRUE 1
-#  define FALSE 0
-#endif
-
-#ifndef MAX
-#  define MAX(a,b)  ((a) > (b)? (a) : (b))
-#  define MIN(a,b)  ((a) < (b)? (a) : (b))
-#endif
-
-#ifdef DEBUG
-#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
-#else
-#  define Trace(x)  ;
-#endif
-
-typedef unsigned char   uch;
-typedef unsigned short  ush;
-typedef unsigned long   ulg;
-
-
-/* prototypes for public functions in readpng.c */
-
-void readpng_version_info(void);
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight);
-
-int readpng_get_bgcolor(uch *bg_red, uch *bg_green, uch *bg_blue);
-
-uch *readpng_get_image(double display_exponent, int *pChannels,
-                       ulg *pRowbytes);
-
-void readpng_cleanup(int free_image_data);
diff --git a/contrib/gregbook/readpng2.c b/contrib/gregbook/readpng2.c
deleted file mode 100644
index 4d5e38f..0000000
--- a/contrib/gregbook/readpng2.c
+++ /dev/null
@@ -1,520 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                 readpng2.c
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2015 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-     2015-11-12 - Check return value of png_get_bKGD() (Glenn R-P)
-
-  ---------------------------------------------------------------------------*/
-
-
-#include <stdlib.h>     /* for exit() prototype */
-#include <setjmp.h>
-
-#include <zlib.h>
-#include "png.h"        /* libpng header from the local directory */
-#include "readpng2.h"   /* typedefs, common macros, public prototypes */
-
-
-/* local prototypes */
-
-static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr);
-static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
-                                 png_uint_32 row_num, int pass);
-static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
-static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
-static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg);
-
-
-
-
-void readpng2_version_info(void)
-{
-    fprintf(stderr, "   Compiled with libpng %s; using libpng %s\n",
-      PNG_LIBPNG_VER_STRING, png_libpng_ver);
-
-    fprintf(stderr, "   and with zlib %s; using zlib %s.\n",
-      ZLIB_VERSION, zlib_version);
-}
-
-
-
-
-int readpng2_check_sig(uch *sig, int num)
-{
-    return !png_sig_cmp(sig, 0, num);
-}
-
-
-
-
-/* returns 0 for success, 2 for libpng problem, 4 for out of memory */
-
-int readpng2_init(mainprog_info *mainprog_ptr)
-{
-    png_structp  png_ptr;       /* note:  temporary variables! */
-    png_infop  info_ptr;
-
-
-    /* could also replace libpng warning-handler (final NULL), but no need: */
-
-    png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), mainprog_ptr,
-      readpng2_error_handler, readpng2_warning_handler);
-    if (!png_ptr)
-        return 4;   /* out of memory */
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (!info_ptr) {
-        png_destroy_read_struct(&png_ptr, NULL, NULL);
-        return 4;   /* out of memory */
-    }
-
-
-    /* we could create a second info struct here (end_info), but it's only
-     * useful if we want to keep pre- and post-IDAT chunk info separated
-     * (mainly for PNG-aware image editors and converters) */
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function, unless an alternate error handler was installed--
-     * but compatible error handlers must either use longjmp() themselves
-     * (as in this program) or exit immediately, so here we are: */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        return 2;
-    }
-
-
-#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
-    /* prepare the reader to ignore all recognized chunks whose data won't be
-     * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT,
-     * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */
-    {
-        /* These byte strings were copied from png.h.  If a future version
-         * of readpng2.c recognizes more chunks, add them to this list.
-         */
-        static PNG_CONST png_byte chunks_to_process[] = {
-            98,  75,  71,  68, '\0',  /* bKGD */
-           103,  65,  77,  65, '\0',  /* gAMA */
-           115,  82,  71,  66, '\0',  /* sRGB */
-           };
-
-       /* Ignore all chunks except for IHDR, PLTE, tRNS, IDAT, and IEND */
-       png_set_keep_unknown_chunks(png_ptr, -1 /* PNG_HANDLE_CHUNK_NEVER */,
-          NULL, -1);
-
-       /* But do not ignore chunks in the "chunks_to_process" list */
-       png_set_keep_unknown_chunks(png_ptr,
-          0 /* PNG_HANDLE_CHUNK_AS_DEFAULT */, chunks_to_process,
-          sizeof(chunks_to_process)/5);
-    }
-#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */
-
-
-    /* instead of doing png_init_io() here, now we set up our callback
-     * functions for progressive decoding */
-
-    png_set_progressive_read_fn(png_ptr, mainprog_ptr,
-      readpng2_info_callback, readpng2_row_callback, readpng2_end_callback);
-
-
-    /* make sure we save our pointers for use in readpng2_decode_data() */
-
-    mainprog_ptr->png_ptr = png_ptr;
-    mainprog_ptr->info_ptr = info_ptr;
-
-
-    /* and that's all there is to initialization */
-
-    return 0;
-}
-
-
-
-
-/* returns 0 for success, 2 for libpng (longjmp) problem */
-
-int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-
-    /* setjmp() must be called in every function that calls a PNG-reading
-     * libpng function */
-
-    if (setjmp(mainprog_ptr->jmpbuf)) {
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-        mainprog_ptr->png_ptr = NULL;
-        mainprog_ptr->info_ptr = NULL;
-        return 2;
-    }
-
-
-    /* hand off the next chunk of input data to libpng for decoding */
-
-    png_process_data(png_ptr, info_ptr, rawbuf, length);
-
-    return 0;
-}
-
-
-
-
-static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
-{
-    mainprog_info  *mainprog_ptr;
-    int  color_type, bit_depth;
-    png_uint_32 width, height;
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-    double  gamma;
-#else
-    png_fixed_point gamma;
-#endif
-
-
-    /* setjmp() doesn't make sense here, because we'd either have to exit(),
-     * longjmp() ourselves, or return control to libpng, which doesn't want
-     * to see us again.  By not doing anything here, libpng will instead jump
-     * to readpng2_decode_data(), which can return an error value to the main
-     * program. */
-
-
-    /* retrieve the pointer to our special-purpose struct, using the png_ptr
-     * that libpng passed back to us (i.e., not a global this time--there's
-     * no real difference for a single image, but for a multithreaded browser
-     * decoding several PNG images at the same time, one needs to avoid mixing
-     * up different images' structs) */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-    if (mainprog_ptr == NULL) {         /* we be hosed */
-        fprintf(stderr,
-          "readpng2 error:  main struct not recoverable in info_callback.\n");
-        fflush(stderr);
-        return;
-        /*
-         * Alternatively, we could call our error-handler just like libpng
-         * does, which would effectively terminate the program.  Since this
-         * can only happen if png_ptr gets redirected somewhere odd or the
-         * main PNG struct gets wiped, we're probably toast anyway.  (If
-         * png_ptr itself is NULL, we would not have been called.)
-         */
-    }
-
-
-    /* this is just like in the non-progressive case */
-
-    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
-       NULL, NULL, NULL);
-    mainprog_ptr->width = (ulg)width;
-    mainprog_ptr->height = (ulg)height;
-
-
-    /* since we know we've read all of the PNG file's "header" (i.e., up
-     * to IDAT), we can check for a background color here */
-
-    if (mainprog_ptr->need_bgcolor)
-    {
-        png_color_16p pBackground;
-
-        /* it is not obvious from the libpng documentation, but this function
-         * takes a pointer to a pointer, and it always returns valid red,
-         * green and blue values, regardless of color_type: */
-        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
-        {
-
-           /* however, it always returns the raw bKGD data, regardless of any
-            * bit-depth transformations, so check depth and adjust if necessary
-            */
-           if (bit_depth == 16) {
-               mainprog_ptr->bg_red   = pBackground->red   >> 8;
-               mainprog_ptr->bg_green = pBackground->green >> 8;
-               mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
-           } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
-               if (bit_depth == 1)
-                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                     mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
-               else if (bit_depth == 2)
-                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                     mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
-               else /* bit_depth == 4 */
-                   mainprog_ptr->bg_red = mainprog_ptr->bg_green =
-                     mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
-           } else {
-               mainprog_ptr->bg_red   = (uch)pBackground->red;
-               mainprog_ptr->bg_green = (uch)pBackground->green;
-               mainprog_ptr->bg_blue  = (uch)pBackground->blue;
-           }
-        }
-    }
-
-
-    /* as before, let libpng expand palette images to RGB, low-bit-depth
-     * grayscale images to 8 bits, transparency chunks to full alpha channel;
-     * strip 16-bit-per-sample images to 8 bits per sample; and convert
-     * grayscale to RGB[A] */
-
-    if (color_type == PNG_COLOR_TYPE_PALETTE)
-        png_set_expand(png_ptr);
-    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
-        png_set_expand(png_ptr);
-    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
-        png_set_expand(png_ptr);
-#ifdef PNG_READ_16_TO_8_SUPPORTED
-    if (bit_depth == 16)
-#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
-        png_set_scale_16(png_ptr);
-#  else
-        png_set_strip_16(png_ptr);
-#  endif
-#endif
-    if (color_type == PNG_COLOR_TYPE_GRAY ||
-        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-        png_set_gray_to_rgb(png_ptr);
-
-
-    /* Unlike the basic viewer, which was designed to operate on local files,
-     * this program is intended to simulate a web browser--even though we
-     * actually read from a local file, too.  But because we are pretending
-     * that most of the images originate on the Internet, we follow the recom-
-     * mendation of the sRGB proposal and treat unlabelled images (no gAMA
-     * chunk) as existing in the sRGB color space.  That is, we assume that
-     * such images have a file gamma of 0.45455, which corresponds to a PC-like
-     * display system.  This change in assumptions will have no effect on a
-     * PC-like system, but on a Mac, SGI, NeXT or other system with a non-
-     * identity lookup table, it will darken unlabelled images, which effec-
-     * tively favors images from PC-like systems over those originating on
-     * the local platform.  Note that mainprog_ptr->display_exponent is the
-     * "gamma" value for the entire display system, i.e., the product of
-     * LUT_exponent and CRT_exponent. */
-
-#ifdef PNG_FLOATING_POINT_SUPPORTED
-    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
-        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma);
-    else
-        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455);
-#else
-    if (png_get_gAMA_fixed(png_ptr, info_ptr, &gamma))
-        png_set_gamma_fixed(png_ptr,
-            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), gamma);
-    else
-        png_set_gamma_fixed(png_ptr,
-            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), 45455);
-#endif
-
-    /* we'll let libpng expand interlaced images, too */
-
-    mainprog_ptr->passes = png_set_interlace_handling(png_ptr);
-
-
-    /* all transformations have been registered; now update info_ptr data and
-     * then get rowbytes and channels */
-
-    png_read_update_info(png_ptr, info_ptr);
-
-    mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr);
-    mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr);
-
-
-    /* Call the main program to allocate memory for the image buffer and
-     * initialize windows and whatnot.  (The old-style function-pointer
-     * invocation is used for compatibility with a few supposedly ANSI
-     * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */
-
-    (*mainprog_ptr->mainprog_init)();
-
-
-    /* and that takes care of initialization */
-
-    return;
-}
-
-
-
-
-
-static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
-                                  png_uint_32 row_num, int pass)
-{
-    mainprog_info  *mainprog_ptr;
-
-
-    /* first check whether the row differs from the previous pass; if not,
-     * nothing to combine or display */
-
-    if (!new_row)
-        return;
-
-
-    /* retrieve the pointer to our special-purpose struct so we can access
-     * the old rows and image-display callback function */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-
-    /* save the pass number for optional use by the front end */
-
-    mainprog_ptr->pass = pass;
-
-
-    /* have libpng either combine the new row data with the existing row data
-     * from previous passes (if interlaced) or else just copy the new row
-     * into the main program's image buffer */
-
-    png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num],
-      new_row);
-
-
-    /* finally, call the display routine in the main program with the number
-     * of the row we just updated */
-
-    (*mainprog_ptr->mainprog_display_row)(row_num);
-
-
-    /* and we're ready for more */
-
-    return;
-}
-
-
-
-
-
-static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)
-{
-    mainprog_info  *mainprog_ptr;
-
-
-    /* retrieve the pointer to our special-purpose struct */
-
-    mainprog_ptr = png_get_progressive_ptr(png_ptr);
-
-
-    /* let the main program know that it should flush any buffered image
-     * data to the display now and set a "done" flag or whatever, but note
-     * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do
-     * NOT call readpng2_cleanup() either here or in the finish_display()
-     * routine; wait until control returns to the main program via
-     * readpng2_decode_data() */
-
-    (*mainprog_ptr->mainprog_finish_display)();
-
-
-    /* all done */
-
-    (void)info_ptr; /* Unused */
-
-    return;
-}
-
-
-
-
-
-void readpng2_cleanup(mainprog_info *mainprog_ptr)
-{
-    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
-    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
-
-    if (png_ptr && info_ptr)
-        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-
-    mainprog_ptr->png_ptr = NULL;
-    mainprog_ptr->info_ptr = NULL;
-}
-
-
-static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg)
-{
-    fprintf(stderr, "readpng2 libpng warning: %s\n", msg);
-    fflush(stderr);
-    (void)png_ptr; /* Unused */
-}
-
-
-static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg)
-{
-    mainprog_info  *mainprog_ptr;
-
-    /* This function, aside from the extra step of retrieving the "error
-     * pointer" (below) and the fact that it exists within the application
-     * rather than within libpng, is essentially identical to libpng's
-     * default error handler.  The second point is critical:  since both
-     * setjmp() and longjmp() are called from the same code, they are
-     * guaranteed to have compatible notions of how big a jmp_buf is,
-     * regardless of whether _BSD_SOURCE or anything else has (or has not)
-     * been defined. */
-
-    fprintf(stderr, "readpng2 libpng error: %s\n", msg);
-    fflush(stderr);
-
-    mainprog_ptr = png_get_error_ptr(png_ptr);
-    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
-        fprintf(stderr,
-          "readpng2 severe error:  jmpbuf not recoverable; terminating.\n");
-        fflush(stderr);
-        exit(99);
-    }
-
-    /* Now we have our data structure we can use the information in it
-     * to return control to our own higher level code (all the points
-     * where 'setjmp' is called in this file.)  This will work with other
-     * error handling mechanisms as well - libpng always calls png_error
-     * when it can proceed no further, thus, so long as the error handler
-     * is intercepted, application code can do its own error recovery.
-     */
-    longjmp(mainprog_ptr->jmpbuf, 1);
-}
diff --git a/contrib/gregbook/readpng2.h b/contrib/gregbook/readpng2.h
deleted file mode 100644
index 6b3660d..0000000
--- a/contrib/gregbook/readpng2.h
+++ /dev/null
@@ -1,116 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng2 - progressive-model PNG display program                 readpng2.h
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#ifndef TRUE
-#  define TRUE 1
-#  define FALSE 0
-#endif
-
-#ifndef MAX
-#  define MAX(a,b)  ((a) > (b)? (a) : (b))
-#  define MIN(a,b)  ((a) < (b)? (a) : (b))
-#endif
-
-#ifdef DEBUG
-#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
-#else
-#  define Trace(x)  ;
-#endif
-
-enum rpng2_states {
-    kPreInit = 0,
-    kWindowInit,
-    kDone
-};
-
-typedef unsigned char   uch;
-typedef unsigned short  ush;
-typedef unsigned long   ulg;
-
-typedef struct _mainprog_info {
-    double display_exponent;
-    ulg width;
-    ulg height;
-    void *png_ptr;
-    void *info_ptr;
-    void (*mainprog_init)(void);
-    void (*mainprog_display_row)(ulg row_num);
-    void (*mainprog_finish_display)(void);
-    uch *image_data;
-    uch **row_pointers;
-    jmp_buf jmpbuf;
-    int passes;              /* not used */
-    int pass;
-    int rowbytes;
-    int channels;
-    int need_bgcolor;
-    int state;
-    uch bg_red;
-    uch bg_green;
-    uch bg_blue;
-} mainprog_info;
-
-
-/* prototypes for public functions in readpng2.c */
-
-void readpng2_version_info(void);
-
-int readpng2_check_sig(uch *sig, int num);
-
-int readpng2_init(mainprog_info *mainprog_ptr);
-
-int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length);
-
-void readpng2_cleanup(mainprog_info *mainprog_ptr);
diff --git a/contrib/gregbook/readppm.c b/contrib/gregbook/readppm.c
deleted file mode 100644
index 7fefc39..0000000
--- a/contrib/gregbook/readppm.c
+++ /dev/null
@@ -1,183 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                              readppm.c
-
-  ---------------------------------------------------------------------------
-
-   This is a special-purpose replacement for readpng.c that allows binary
-   PPM files to be used in place of PNG images.
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "readpng.h"    /* typedefs, common macros, public prototypes */
-
-
-ulg  width, height;
-int  bit_depth, color_type, channels;
-uch  *image_data = NULL;
-FILE *saved_infile;
-
-
-void readpng_version_info()
-{
-    fprintf(stderr, "   Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
-}
-
-
-/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
-
-int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
-{
-    static uch ppmline[256];
-    int maxval;
-
-
-    saved_infile = infile;
-
-    fgets(ppmline, 256, infile);
-    if (ppmline[0] != 'P' || ppmline[1] != '6') {
-        fprintf(stderr, "ERROR:  not a PPM file\n");
-        return 1;
-    }
-    /* possible color types:  P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
-    if (ppmline[1] == '6') {
-        color_type = 2;
-        channels = 3;
-    } else if (ppmline[1] == '8') {
-        color_type = 6;
-        channels = 4;
-    } else /* if (ppmline[1] == '5') */ {
-        color_type = 0;
-        channels = 1;
-    }
-
-    do {
-        fgets(ppmline, 256, infile);
-    } while (ppmline[0] == '#');
-    sscanf(ppmline, "%lu %lu", &width, &height);
-
-    do {
-        fgets(ppmline, 256, infile);
-    } while (ppmline[0] == '#');
-    sscanf(ppmline, "%d", &maxval);
-    if (maxval != 255) {
-        fprintf(stderr, "ERROR:  maxval = %d\n", maxval);
-        return 2;
-    }
-    bit_depth = 8;
-
-    *pWidth = width;
-    *pHeight = height;
-
-    return 0;
-}
-
-
-
-
-/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
- * scales values to 8-bit if necessary */
-
-int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
-{
-    return 1;
-}
-
-
-
-
-/* display_exponent == LUT_exponent * CRT_exponent */
-
-uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
-{
-    ulg  rowbytes;
-
-
-    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
-     * transparency chunks to full alpha channel; strip 16-bit-per-sample
-     * images to 8 bits per sample; and convert grayscale to RGB[A] */
-
-    /* GRR WARNING:  grayscale needs to be expanded and channels reset! */
-
-    *pRowbytes = rowbytes = channels*width;
-    *pChannels = channels;
-
-    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
-        return NULL;
-    }
-
-    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
-
-
-    /* now we can go ahead and just read the whole image */
-
-    if (fread(image_data, 1L, rowbytes*height, saved_infile) <
-       rowbytes*height) {
-        free (image_data);
-        image_data = NULL;
-        return NULL;
-    }
-
-    return image_data;
-}
-
-
-void readpng_cleanup(int free_image_data)
-{
-    if (free_image_data && image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-}
diff --git a/contrib/gregbook/rpng-win.c b/contrib/gregbook/rpng-win.c
deleted file mode 100644
index f53ddc8..0000000
--- a/contrib/gregbook/rpng-win.c
+++ /dev/null
@@ -1,728 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                             rpng-win.c
-
-   This program decodes and displays PNG images, with gamma correction and
-   optionally with a user-specified background color (in case the image has
-   transparency).  It is very nearly the most basic PNG viewer possible.
-   This version is for 32-bit Windows; it may compile under 16-bit Windows
-   with a little tweaking (or maybe not).
-
-   to do:
-    - handle quoted command-line args (especially filenames with spaces)
-    - have minimum window width:  oh well
-    - use %.1023s to simplify truncation of title-bar string?
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.00:  initial public release
-    - 1.01:  modified to allow abbreviated options; fixed long/ulong mis-
-              match; switched to png_jmpbuf() macro
-    - 1.02:  added extra set of parentheses to png_jmpbuf() macro; fixed
-              command-line parsing bug
-    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed improper display of usage screen on PNG error(s)
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng-win"
-#define LONGNAME  "Simple PNG Viewer for Windows"
-#define VERSION   "2.01 of 16 March 2008"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <windows.h>
-#ifdef __CYGWIN__
-/* getch replacement. Turns out, we don't really need this,
- * but leave it here if we ever enable any of the uses of
- * _getch in the main code
- */
-#include <unistd.h>
-#include <termio.h>
-#include <sys/ioctl.h>
-int repl_getch( void )
-{
-  char ch;
-  int fd = fileno(stdin);
-  struct termio old_tty, new_tty;
-
-  ioctl(fd, TCGETA, &old_tty);
-  new_tty = old_tty;
-  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
-  ioctl(fd, TCSETA, &new_tty);
-  fread(&ch, 1, sizeof(ch), stdin);
-  ioctl(fd, TCSETA, &old_tty);
-
-  return ch;
-}
-#define _getch repl_getch
-#else
-#include <conio.h>      /* only for _getch() */
-#endif
-
-/* #define DEBUG  :  this enables the Trace() macros */
-
-#include "readpng.h"    /* typedefs, common macros, readpng prototypes */
-
-
-/* could just include png.h, but this macro is the only thing we need
- * (name and typedefs changed to local versions); note that side effects
- * only happen with alpha (which could easily be avoided with
- * "ush acopy = (alpha);") */
-
-#define alpha_composite(composite, fg, alpha, bg) {               \
-    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
-                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
-    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
-}
-
-
-/* local prototypes */
-static int        rpng_win_create_window(HINSTANCE hInst, int showmode);
-static int        rpng_win_display_image(void);
-static void       rpng_win_cleanup(void);
-LRESULT CALLBACK  rpng_win_wndproc(HWND, UINT, WPARAM, LPARAM);
-
-
-static char titlebar[1024];
-static char *progname = PROGNAME;
-static char *appname = LONGNAME;
-static char *filename;
-static FILE *infile;
-
-static char *bgstr;
-static uch bg_red=0, bg_green=0, bg_blue=0;
-
-static double display_exponent;
-
-static ulg image_width, image_height, image_rowbytes;
-static int image_channels;
-static uch *image_data;
-
-/* Windows-specific variables */
-static ulg wimage_rowbytes;
-static uch *dib;
-static uch *wimage_data;
-static BITMAPINFOHEADER *bmih;
-
-static HWND global_hwnd;
-
-
-
-
-int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
-{
-    char *args[1024];                 /* arbitrary limit, but should suffice */
-    char *p, *q, **argv = args;
-    int argc = 0;
-    int rc, alen, flen;
-    int error = 0;
-    int have_bg = FALSE;
-    double LUT_exponent;              /* just the lookup table */
-    double CRT_exponent = 2.2;        /* just the monitor */
-    double default_display_exponent;  /* whole display system */
-    MSG msg;
-
-
-    filename = (char *)NULL;
-
-#ifndef __CYGWIN__
-    /* First reenable console output, which normally goes to the bit bucket
-     * for windowed apps.  Closing the console window will terminate the
-     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
-     * incantation. */
-
-    AllocConsole();
-    freopen("CONOUT$", "a", stderr);
-    freopen("CONOUT$", "a", stdout);
-#endif
-
-
-    /* Next set the default value for our display-system exponent, i.e.,
-     * the product of the CRT exponent and the exponent corresponding to
-     * the frame-buffer's lookup table (LUT), if any.  This is not an
-     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
-     * ones), but it should cover 99% of the current possibilities.  And
-     * yes, these ifdefs are completely wasted in a Windows program... */
-
-#if defined(NeXT)
-    LUT_exponent = 1.0 / 2.2;
-    /*
-    if (some_next_function_that_returns_gamma(&next_gamma))
-        LUT_exponent = 1.0 / next_gamma;
-     */
-#elif defined(sgi)
-    LUT_exponent = 1.0 / 1.7;
-    /* there doesn't seem to be any documented function to get the
-     * "gamma" value, so we do it the hard way */
-    infile = fopen("/etc/config/system.glGammaVal", "r");
-    if (infile) {
-        double sgi_gamma;
-
-        fgets(tmpline, 80, infile);
-        fclose(infile);
-        sgi_gamma = atof(tmpline);
-        if (sgi_gamma > 0.0)
-            LUT_exponent = 1.0 / sgi_gamma;
-    }
-#elif defined(Macintosh)
-    LUT_exponent = 1.8 / 2.61;
-    /*
-    if (some_mac_function_that_returns_gamma(&mac_gamma))
-        LUT_exponent = mac_gamma / 2.61;
-     */
-#else
-    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
-#endif
-
-    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
-    default_display_exponent = LUT_exponent * CRT_exponent;
-
-
-    /* If the user has set the SCREEN_GAMMA environment variable as suggested
-     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
-     * use the default value we just calculated.  Either way, the user may
-     * override this via a command-line option. */
-
-    if ((p = getenv("SCREEN_GAMMA")) != NULL)
-        display_exponent = atof(p);
-    else
-        display_exponent = default_display_exponent;
-
-
-    /* Windows really hates command lines, so we have to set up our own argv.
-     * Note that we do NOT bother with quoted arguments here, so don't use
-     * filenames with spaces in 'em! */
-
-    argv[argc++] = PROGNAME;
-    p = cmd;
-    for (;;) {
-        if (*p == ' ')
-            while (*++p == ' ')
-                ;
-        /* now p points at the first non-space after some spaces */
-        if (*p == '\0')
-            break;    /* nothing after the spaces:  done */
-        argv[argc++] = q = p;
-        while (*q && *q != ' ')
-            ++q;
-        /* now q points at a space or the end of the string */
-        if (*q == '\0')
-            break;    /* last argv already terminated; quit */
-        *q = '\0';    /* change space to terminator */
-        p = q + 1;
-    }
-    argv[argc] = NULL;   /* terminate the argv array itself */
-
-
-    /* Now parse the command line for options and the PNG filename. */
-
-    while (*++argv && !error) {
-        if (!strncmp(*argv, "-gamma", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                display_exponent = atof(*argv);
-                if (display_exponent <= 0.0)
-                    ++error;
-            }
-        } else if (!strncmp(*argv, "-bgcolor", 2)) {
-            if (!*++argv)
-                ++error;
-            else {
-                bgstr = *argv;
-                if (strlen(bgstr) != 7 || bgstr[0] != '#')
-                    ++error;
-                else
-                    have_bg = TRUE;
-            }
-        } else {
-            if (**argv != '-') {
-                filename = *argv;
-                if (argv[1])   /* shouldn't be any more args after filename */
-                    ++error;
-            } else
-                ++error;   /* not expecting any other options */
-        }
-    }
-
-    if (!filename)
-        ++error;
-
-
-    /* print usage screen if any errors up to this point */
-
-    if (error) {
-#ifndef __CYGWIN__
-        int ch;
-#endif
-
-        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
-        readpng_version_info();
-        fprintf(stderr, "\n"
-          "Usage:  %s [-gamma exp] [-bgcolor bg] file.png\n"
-          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
-          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
-          "\t\t  to the product of the lookup-table exponent (varies)\n"
-          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
-          "    bg  \tdesired background color in 7-character hex RGB format\n"
-          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
-          "\t\t  used with transparent images\n"
-          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
-#ifndef __CYGWIN__
-          "Press Q or Esc to quit this usage screen.\n"
-#endif
-          "\n", PROGNAME, default_display_exponent);
-#ifndef __CYGWIN__
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-#endif
-        exit(1);
-    }
-
-
-    if (!(infile = fopen(filename, "rb"))) {
-        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
-        ++error;
-    } else {
-        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
-            switch (rc) {
-                case 1:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] is not a PNG file: incorrect signature\n",
-                      filename);
-                    break;
-                case 2:
-                    fprintf(stderr, PROGNAME
-                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
-                    break;
-                case 4:
-                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
-                    break;
-                default:
-                    fprintf(stderr, PROGNAME
-                      ":  unknown readpng_init() error\n");
-                    break;
-            }
-            ++error;
-        }
-        if (error)
-            fclose(infile);
-    }
-
-
-    if (error) {
-#ifndef __CYGWIN__
-        int ch;
-#endif
-
-        fprintf(stderr, PROGNAME ":  aborting.\n");
-#ifndef __CYGWIN__
-        do
-            ch = _getch();
-        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
-#endif
-        exit(2);
-    } else {
-        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
-#ifndef __CYGWIN__
-        fprintf(stderr,
-          "\n   [console window:  closing this window will terminate %s]\n\n",
-          PROGNAME);
-#endif
-    }
-
-
-    /* set the title-bar string, but make sure buffer doesn't overflow */
-
-    alen = strlen(appname);
-    flen = strlen(filename);
-    if (alen + flen + 3 > 1023)
-        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
-    else
-        sprintf(titlebar, "%s:  %s", appname, filename);
-
-
-    /* if the user didn't specify a background color on the command line,
-     * check for one in the PNG file--if not, the initialized values of 0
-     * (black) will be used */
-
-    if (have_bg) {
-        unsigned r, g, b;   /* this approach quiets compiler warnings */
-
-        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
-        bg_red   = (uch)r;
-        bg_green = (uch)g;
-        bg_blue  = (uch)b;
-    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
-        readpng_cleanup(TRUE);
-        fprintf(stderr, PROGNAME
-          ":  libpng error while checking for background color\n");
-        exit(2);
-    }
-
-
-    /* do the basic Windows initialization stuff, make the window and fill it
-     * with the background color */
-
-    if (rpng_win_create_window(hInst, showmode))
-        exit(2);
-
-
-    /* decode the image, all at once */
-
-    Trace((stderr, "calling readpng_get_image()\n"))
-    image_data = readpng_get_image(display_exponent, &image_channels,
-      &image_rowbytes);
-    Trace((stderr, "done with readpng_get_image()\n"))
-
-
-    /* done with PNG file, so clean up to minimize memory usage (but do NOT
-     * nuke image_data!) */
-
-    readpng_cleanup(FALSE);
-    fclose(infile);
-
-    if (!image_data) {
-        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
-        exit(3);
-    }
-
-
-    /* display image (composite with background if requested) */
-
-    Trace((stderr, "calling rpng_win_display_image()\n"))
-    if (rpng_win_display_image()) {
-        free(image_data);
-        exit(4);
-    }
-    Trace((stderr, "done with rpng_win_display_image()\n"))
-
-
-    /* wait for the user to tell us when to quit */
-
-    printf(
-#ifndef __CYGWIN__
-      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
-#else
-      "Done.  Press mouse button 1 (within image window) to quit.\n"
-#endif
-    );
-    fflush(stdout);
-
-    while (GetMessage(&msg, NULL, 0, 0)) {
-        TranslateMessage(&msg);
-        DispatchMessage(&msg);
-    }
-
-
-    /* OK, we're done:  clean up all image and Windows resources and go away */
-
-    rpng_win_cleanup();
-
-    return msg.wParam;
-}
-
-
-
-
-
-static int rpng_win_create_window(HINSTANCE hInst, int showmode)
-{
-    uch *dest;
-    int extra_width, extra_height;
-    ulg i, j;
-    WNDCLASSEX wndclass;
-
-
-/*---------------------------------------------------------------------------
-    Allocate memory for the display-specific version of the image (round up
-    to multiple of 4 for Windows DIB).
-  ---------------------------------------------------------------------------*/
-
-    wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
-
-    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
-                              wimage_rowbytes*image_height)))
-    {
-        return 4;   /* fail */
-    }
-
-/*---------------------------------------------------------------------------
-    Initialize the DIB.  Negative height means to use top-down BMP ordering
-    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
-    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
-    directly => wimage_data begins immediately after BMP header.
-  ---------------------------------------------------------------------------*/
-
-    memset(dib, 0, sizeof(BITMAPINFOHEADER));
-    bmih = (BITMAPINFOHEADER *)dib;
-    bmih->biSize = sizeof(BITMAPINFOHEADER);
-    bmih->biWidth = image_width;
-    bmih->biHeight = -((long)image_height);
-    bmih->biPlanes = 1;
-    bmih->biBitCount = 24;
-    bmih->biCompression = 0;
-    wimage_data = dib + sizeof(BITMAPINFOHEADER);
-
-/*---------------------------------------------------------------------------
-    Fill in background color (black by default); data are in BGR order.
-  ---------------------------------------------------------------------------*/
-
-    for (j = 0;  j < image_height;  ++j) {
-        dest = wimage_data + j*wimage_rowbytes;
-        for (i = image_width;  i > 0;  --i) {
-            *dest++ = bg_blue;
-            *dest++ = bg_green;
-            *dest++ = bg_red;
-        }
-    }
-
-/*---------------------------------------------------------------------------
-    Set the window parameters.
-  ---------------------------------------------------------------------------*/
-
-    memset(&wndclass, 0, sizeof(wndclass));
-
-    wndclass.cbSize = sizeof(wndclass);
-    wndclass.style = CS_HREDRAW | CS_VREDRAW;
-    wndclass.lpfnWndProc = rpng_win_wndproc;
-    wndclass.hInstance = hInst;
-    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
-    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
-    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
-    wndclass.lpszMenuName = NULL;
-    wndclass.lpszClassName = progname;
-    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
-
-    RegisterClassEx(&wndclass);
-
-/*---------------------------------------------------------------------------
-    Finally, create the window.
-  ---------------------------------------------------------------------------*/
-
-    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
-                      GetSystemMetrics(SM_CXDLGFRAME));
-    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
-                      GetSystemMetrics(SM_CYDLGFRAME)) +
-                      GetSystemMetrics(SM_CYCAPTION);
-
-    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
-      CW_USEDEFAULT, CW_USEDEFAULT, image_width+extra_width,
-      image_height+extra_height, NULL, NULL, hInst, NULL);
-
-    ShowWindow(global_hwnd, showmode);
-    UpdateWindow(global_hwnd);
-
-    return 0;
-
-} /* end function rpng_win_create_window() */
-
-
-
-
-
-static int rpng_win_display_image()
-{
-    uch *src, *dest;
-    uch r, g, b, a;
-    ulg i, row, lastrow;
-    RECT rect;
-
-
-    Trace((stderr, "beginning display loop (image_channels == %d)\n",
-      image_channels))
-    Trace((stderr, "(width = %ld, rowbytes = %ld, wimage_rowbytes = %d)\n",
-      image_width, image_rowbytes, wimage_rowbytes))
-
-
-/*---------------------------------------------------------------------------
-    Blast image data to buffer.  This whole routine takes place before the
-    message loop begins, so there's no real point in any pseudo-progressive
-    display...
-  ---------------------------------------------------------------------------*/
-
-    for (lastrow = row = 0;  row < image_height;  ++row) {
-        src = image_data + row*image_rowbytes;
-        dest = wimage_data + row*wimage_rowbytes;
-        if (image_channels == 3) {
-            for (i = image_width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                *dest++ = b;
-                *dest++ = g;   /* note reverse order */
-                *dest++ = r;
-            }
-        } else /* if (image_channels == 4) */ {
-            for (i = image_width;  i > 0;  --i) {
-                r = *src++;
-                g = *src++;
-                b = *src++;
-                a = *src++;
-                if (a == 255) {
-                    *dest++ = b;
-                    *dest++ = g;
-                    *dest++ = r;
-                } else if (a == 0) {
-                    *dest++ = bg_blue;
-                    *dest++ = bg_green;
-                    *dest++ = bg_red;
-                } else {
-                    /* this macro (copied from png.h) composites the
-                     * foreground and background values and puts the
-                     * result into the first argument; there are no
-                     * side effects with the first argument */
-                    alpha_composite(*dest++, b, a, bg_blue);
-                    alpha_composite(*dest++, g, a, bg_green);
-                    alpha_composite(*dest++, r, a, bg_red);
-                }
-            }
-        }
-        /* display after every 16 lines */
-        if (((row+1) & 0xf) == 0) {
-            rect.left = 0L;
-            rect.top = (LONG)lastrow;
-            rect.right = (LONG)image_width;      /* possibly off by one? */
-            rect.bottom = (LONG)lastrow + 16L;   /* possibly off by one? */
-            InvalidateRect(global_hwnd, &rect, FALSE);
-            UpdateWindow(global_hwnd);     /* similar to XFlush() */
-            lastrow = row + 1;
-        }
-    }
-
-    Trace((stderr, "calling final image-flush routine\n"))
-    if (lastrow < image_height) {
-        rect.left = 0L;
-        rect.top = (LONG)lastrow;
-        rect.right = (LONG)image_width;      /* possibly off by one? */
-        rect.bottom = (LONG)image_height;    /* possibly off by one? */
-        InvalidateRect(global_hwnd, &rect, FALSE);
-        UpdateWindow(global_hwnd);     /* similar to XFlush() */
-    }
-
-/*
-    last param determines whether or not background is wiped before paint
-    InvalidateRect(global_hwnd, NULL, TRUE);
-    UpdateWindow(global_hwnd);
- */
-
-    return 0;
-}
-
-
-
-
-
-static void rpng_win_cleanup()
-{
-    if (image_data) {
-        free(image_data);
-        image_data = NULL;
-    }
-
-    if (dib) {
-        free(dib);
-        dib = NULL;
-    }
-}
-
-
-
-
-
-LRESULT CALLBACK rpng_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
-{
-    HDC         hdc;
-    PAINTSTRUCT ps;
-    int rc;
-
-    switch (iMsg) {
-        case WM_CREATE:
-            /* one-time processing here, if any */
-            return 0;
-
-        case WM_PAINT:
-            hdc = BeginPaint(hwnd, &ps);
-                    /*                    dest                          */
-            rc = StretchDIBits(hdc, 0, 0, image_width, image_height,
-                    /*                    source                        */
-                                    0, 0, image_width, image_height,
-                                    wimage_data, (BITMAPINFO *)bmih,
-                    /*              iUsage: no clue                     */
-                                    0, SRCCOPY);
-            EndPaint(hwnd, &ps);
-            return 0;
-
-        /* wait for the user to tell us when to quit */
-        case WM_CHAR:
-            switch (wP) {      /* only need one, so ignore repeat count */
-                case 'q':
-                case 'Q':
-                case 0x1B:     /* Esc key */
-                    PostQuitMessage(0);
-            }
-            return 0;
-
-        case WM_LBUTTONDOWN:   /* another way of quitting */
-        case WM_DESTROY:
-            PostQuitMessage(0);
-            return 0;
-    }
-
-    return DefWindowProc(hwnd, iMsg, wP, lP);
-}
diff --git a/contrib/gregbook/rpng-x.c b/contrib/gregbook/rpng-x.c
deleted file mode 100644
index ddd7c58..0000000
--- a/contrib/gregbook/rpng-x.c
+++ /dev/null
@@ -1,910 +0,0 @@
-/*---------------------------------------------------------------------------
-
-   rpng - simple PNG display program                               rpng-x.c
-
-   This program decodes and displays PNG images, with gamma correction and
-   optionally with a user-specified background color (in case the image has
-   transparency).  It is very nearly the most basic PNG viewer possible.
-   This version is for the X Window System (tested by author under Unix and
-   by Martin Zinser under OpenVMS; may work under OS/2 with some tweaking).
-
-   to do:
-    - 8-bit (colormapped) X support
-    - use %.1023s to simplify truncation of title-bar string?
-
-  ---------------------------------------------------------------------------
-
-   Changelog:
-    - 1.01:  initial public release
-    - 1.02:  modified to allow abbreviated options; fixed long/ulong mis-
-              match; switched to png_jmpbuf() macro
-    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
-    - 1.11:  added extra set of parentheses to png_jmpbuf() macro; fixed
-              command-line parsing bug
-    - 1.12:  fixed some small X memory leaks (thanks to François Petitjean)
-    - 1.13:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
-    - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
-    - 2.00:  dual-licensed (added GNU GPL)
-    - 2.01:  fixed improper display of usage screen on PNG error(s)
-    - 2.02:  Added "void(argc);" statement to quiet pedantic compiler warnings
-             about unused variable (GR-P)
-
-  ---------------------------------------------------------------------------
-
-      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
-
-      This software is provided "as is," without warranty of any kind,
-      express or implied.  In no event shall the author or contributors
-      be held liable for any damages arising in any way from the use of
-      this software.
-
-      The contents of this file are DUAL-LICENSED.  You may modify and/or
-      redistribute this software according to the terms of one of the
-      following two licenses (at your option):
-
-
-      LICENSE 1 ("BSD-like with advertising clause"):
-
-      Permission is granted to anyone to use this software for any purpose,
-      including commercial applications, and to alter it and redistribute
-      it freely, subject to the following restrictions:
-
-      1. Redistributions of source code must retain the above copyright
-         notice, disclaimer, and this list of conditions.
-      2. Redistributions in binary form must reproduce the above copyright
-         notice, disclaimer, and this list of conditions in the documenta-
-         tion and/or other materials provided with the distribution.
-      3. All advertising materials mentioning features or use of this
-         software must display the following acknowledgment:
-
-            This product includes software developed by Greg Roelofs
-            and contributors for the book, "PNG: The Definitive Guide,"
-            published by O'Reilly and Associates.
-
-
-      LICENSE 2 (GNU GPL v2 or later):
-
-      This program is free software; you can redistribute it and/or modify
-      it under the terms of the GNU General Public License as published by
-      the Free Software Foundation; either version 2 of the License, or
-      (at your option) any later version.
-
-      This program is distributed in the hope that it will be useful,
-      but WITHOUT ANY WARRANTY; without even the implied warranty of
-      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-      GNU General Public License for more details.
-
-      You should have received a copy of the GNU General Public License
-      along with this program; if not, write to the Free Software Foundation,
-      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-  ---------------------------------------------------------------------------*/
-
-#define PROGNAME  "rpng-x"
-#define LONGNAME  "Simple PNG Viewer for X"
-#define VERSION   "2.02 of 15 June 2014"
-#define RESNAME   "rpng"        /* our X resource application name */
-#define RESCLASS  "Rpng"        /* our X resource class name */
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <X11/Xlib.h>
-#include <X11/Xutil.h>
-#include <X11/Xos.h>
-#include <X11/keysym.h>
-
-/* #def