fontconfig: add patch for universal builds

fontconfig fails to build universally due to SIZEOF_VOID issues
that are solved by adapting the Macports patch for that to our
newer version of fontconfig.

Closes Homebrew/homebrew#15567.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/fontconfig.rb

@@ -12,9 +12,38 @@ class Fontconfig < Formula
   depends_on :freetype
   depends_on 'pkg-config' => :build
 
+  # Patch adapted from Macports patch for 2.9.0 defines sizeof based on __LP64__
+  # Fixes universal builds but seems groovy enough to apply in all cases.
+  # https://trac.macports.org/browser/trunk/dports/graphics/fontconfig/files/patch-check-arch-at-runtime.diff
+  def patches; DATA; end
+
   def install
     ENV.universal_binary if build.universal?
     system "./configure", "--disable-dependency-tracking", "--prefix=#{prefix}"
     system "make install"
   end
 end
+
+__END__
+--- a/src/fcarch.h	2012-07-23 19:01:32.000000000 -0700
++++ b/src/fcarch.h	2012-10-20 10:29:15.000000000 -0700
+@@ -46,6 +46,19 @@
+  * be64		1234		8		8
+  */
+
++#ifdef __APPLE__
++# include <machine/endian.h>
++# undef SIZEOF_VOID_P
++# undef ALIGNOF_DOUBLE
++# ifdef __LP64__
++#  define SIZEOF_VOID_P 8
++#  define ALIGNOF_DOUBLE 8
++# else
++#  define SIZEOF_VOID_P 4
++#  define ALIGNOF_DOUBLE 4
++# endif
++#endif
++
+ #if defined(__DARWIN_BYTE_ORDER) && __DARWIN_BYTE_ORDER == __DARWIN_LITTLE_ENDIAN
+ # define FC_ARCH_ENDIAN "le"
+ #elif defined(__DARWIN_BYTE_ORDER) && __DARWIN_BYTE_ORDER == __DARWIN_BIG_ENDIAN