component/fontconfig: Bump fontconfig version (fix for FTBFS with glibc 2.25).

https://cgit.freedesktop.org/fontconfig/commit/?id=1ab5258f7c2abfafcd63a760ca08bf93591912da

fontconfig > 2.12.1 now requires gperf.

component/fontconfig/buildout.cfg

@@ -7,14 +7,15 @@ extends =
   ../bzip2/buildout.cfg
   ../zlib/buildout.cfg
   ../bzip2/buildout.cfg
+  ../gperf/buildout.cfg
 
 parts =
   fontconfig
 
 [fontconfig]
 recipe = slapos.recipe.cmmi
-url = http://fontconfig.org/release/fontconfig-2.12.1.tar.bz2
-md5sum = b5af5a423ee3b5cfc34846838963c058
+url = http://fontconfig.org/release/fontconfig-2.12.6.tar.bz2
+md5sum = 733f5e2371ca77b69707bd7b30cc2163
 pkg_config_depends = ${freetype:pkg_config_depends}:${freetype:location}/lib/pkgconfig:${libxml2:location}/lib/pkgconfig
 # XXX-Cedric : should we use --with-add-fonts={somefont:location}/share,{someotherfont:location}/share?
 configure-options =
@@ -23,7 +24,7 @@ configure-options =
   --enable-libxml2
   --with-default-fonts=${fonts:location}
 environment =
-  PATH=${pkgconfig:location}/bin:%(PATH)s
+  PATH=${pkgconfig:location}/bin:${gperf:location}/bin:%(PATH)s
   PKG_CONFIG_PATH=${:pkg_config_depends}
   CPPFLAGS=-I${zlib:location}/include -I${bzip2:location}/include
   LDFLAGS=-L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib -L${bzip2:location}/lib -Wl,-rpath=${bzip2:location}/lib