Index: libffi/README
===================================================================
--- libffi.orig/README
+++ libffi/README
@@ -116,9 +116,13 @@ It's also possible to build libffi on Wi
 Microsoft's Visual C++ compiler.  In this case, use the msvcc.sh
 wrapper script during configuration like so:
 
-path/to/configure --enable-shared --enable-static \
-	CC=path/to/msvcc.sh LD=link \
-	CPP=\"cl -nologo -EP\"
+path/to/configure CC=path/to/msvcc.sh LD=link CPP=\"cl -nologo -EP\"
+
+For 64-bit Windows builds, use CC="path/to/msvcc.sh -m64".
+You may also need to specify --build appropriately. When building with MSVC
+under a MingW environment, you may need to remove the line in configure
+that sets 'fix_srcfile_path' to a 'cygpath' command. ('cygpath' is not
+present in MingW, and is not required when using MingW-style paths.)
 
 Configure has many other options. Use "configure --help" to see them all.
 
Index: libffi/msvcc.sh
===================================================================
--- libffi.orig/msvcc.sh
+++ libffi/msvcc.sh
@@ -42,7 +42,7 @@
 # format and translated into something sensible for cl or ml.
 #
 
-args="-nologo"
+args="-nologo -W3"
 md=-MD
 cl="cl"
 ml="ml"
@@ -65,13 +65,25 @@ do
       ml="ml64" # "$MSVC/x86_amd64/ml64"
       shift 1
     ;;
+    -O0)
+      args="$args -Od"
+      shift 1
+    ;;
     -O*)
-      args="$args $1"
+      # If we're optimizing, make sure we explicitly turn on some optimizations
+      # that are implicitly disabled by debug symbols (-Zi).
+      args="$args $1 -OPT:REF -OPT:ICF -INCREMENTAL:NO"
       shift 1
     ;;
     -g)
-      # Can't specify -RTC1 or -Zi in opt. -Gy is ok. Use -OPT:REF?
-      args="$args -D_DEBUG -RTC1 -Zi"
+      # Enable debug symbol generation.
+      args="$args -Zi -DEBUG"
+      shift 1
+    ;;
+    -DFFI_DEBUG)
+      # Link against debug CRT and enable runtime error checks.
+      args="$args -RTC1"
+      defines="$defines $1"
       md=-MDd
       shift 1
     ;;
@@ -108,8 +120,8 @@ do
       shift 1
     ;;
     -Wall)
-      # -Wall on MSVC is overzealous. Use -W3 instead.
-      args="$args -W3"
+      # -Wall on MSVC is overzealous, and we already build with -W3. Nothing
+      # to do here.
       shift 1
     ;;
     -Werror)
Index: libffi/ChangeLog
===================================================================
--- libffi.orig/ChangeLog
+++ libffi/ChangeLog
@@ -231,6 +231,11 @@
 	* man/Makefile.in: Regenerate.
 	* testsuite/Makefile.in: Regenerate.
 
+2010-03-30  Dan Witte  <dwitte@mozilla.com>
+
+	* msvcc.sh: Disable build warnings.
+	* README (tested): Clarify windows build procedure.
+
 2010-03-15  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
 	* configure.ac (libffi_cv_as_x86_64_unwind_section_type): New test.