Add Fuchsia build files

This adds a BUILD.gn file for Fuchsia.

Change-Id: I92f9148b6ce8fab2fb0d429d3f60dd73c58b2760
diff --git a/BUILD.gn b/BUILD.gn
new file mode 100644
index 0000000..f6a1595
--- /dev/null
+++ b/BUILD.gn
@@ -0,0 +1,102 @@
+# Copyright 2017 The Fuchsia Authors. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#    * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#    * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#    * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+config("zlib_config") {
+  include_dirs = [ "." ]
+}
+
+config("zlib_warnings") {
+  visibility = [ ":*" ]
+
+  cflags = [
+    "-Wno-implicit-function-declaration",
+  ]
+}
+
+static_library("zlib") {
+  sources = [
+    "adler32.c",
+    "compress.c",
+    "crc32.c",
+    "crc32.h",
+    "deflate.c",
+    "deflate.h",
+    "gzclose.c",
+    "gzguts.h",
+    "gzlib.c",
+    "gzread.c",
+    "gzwrite.c",
+    "infback.c",
+    "inffast.c",
+    "inffast.h",
+    "inffixed.h",
+    "inflate.c",
+    "inflate.h",
+    "inftrees.c",
+    "inftrees.h",
+    "trees.c",
+    "trees.h",
+    "uncompr.c",
+    "zconf.h",
+    "zlib.h",
+    "zutil.c",
+    "zutil.h",
+  ]
+
+  configs += [ ":zlib_warnings" ]
+  public_configs = [ ":zlib_config" ]
+}
+
+config("minizip_warnings") {
+  visibility = [ ":*" ]
+
+  cflags = [
+    "-Wno-implicit-function-declaration",
+  ]
+
+  if (is_clang) {
+    # minizip uses `if ((a == b))` for some reason.
+    cflags += [ "-Wno-parentheses-equality" ]
+  }
+}
+
+static_library("minizip") {
+  sources = [
+    "contrib/minizip/crypt.h",
+    "contrib/minizip/ioapi.c",
+    "contrib/minizip/ioapi.h",
+    "contrib/minizip/unzip.c",
+    "contrib/minizip/unzip.h",
+    "contrib/minizip/zip.c",
+    "contrib/minizip/zip.h",
+  ]
+
+  deps = [ ":zlib" ]
+  configs += [ ":minizip_warnings" ]
+  public_configs = [ ":zlib_config" ]
+}