gnu: icecat: Add patch to adapt to freetype 2.6.

* gnu/packages/patches/icecat-freetype-2.6.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/gnuzilla.scm (icecat)[source]: Add patch.

gnu-system.am

@@ -469,6 +469,7 @@ dist_patch_DATA =						\
   gnu/packages/patches/hydra-automake-1.15.patch		\
   gnu/packages/patches/hydra-disable-darcs-test.patch		\
   gnu/packages/patches/icecat-enable-acceleration-and-webgl.patch \
+  gnu/packages/patches/icecat-freetype-2.6.patch		\
   gnu/packages/patches/icecat-libvpx-1.4.patch			\
   gnu/packages/patches/irrlicht-mesa-10.patch			\
   gnu/packages/patches/jbig2dec-ignore-testtest.patch		\

gnu/packages/gnuzilla.scm

@@ -279,6 +279,7 @@ (define-public icecat
                       "db/sqlite3"))
           #t))
       (patches (map search-patch '("icecat-enable-acceleration-and-webgl.patch"
+                                   "icecat-freetype-2.6.patch"
                                    "icecat-libvpx-1.4.patch")))))
     (build-system gnu-build-system)
     (inputs

gnu/packages/patches/icecat-freetype-2.6.patch

@@ -0,0 +1,14 @@
+Adapt to freetype 2.6.  This patch copied from upstream, see:
+https://bugzilla.mozilla.org/show_bug.cgi?id=1143411
+https://hg.mozilla.org/mozilla-central/rev/afd840d66e6a
+
+--- a/config/system-headers
++++ b/config/system-headers
+@@ -415,6 +415,7 @@ freetype/ftbitmap.h
+ freetype/ftxf86.h
+ freetype.h
+ ftcache.h
++ftfntfmt.h
+ ftglyph.h
+ ftsynth.h
+ ftoutln.h