Python: use the system FFI.

* The built-in one does not work which leads to missing the ctype
package (used for example in youtube_dl).

dev-lang/python/python-2.7.6.recipe

@@ -13,7 +13,7 @@ LICENSE="Python"
 COPYRIGHT="1990-2012, Python Software Foundation"
 SRC_URI="https://www.python.org/ftp/python/2.7.6/Python-2.7.6.tar.xz"
 CHECKSUM_SHA256="1fd68e81f8bf7386ff239b7faee9ba387129d2cf34eab13350bd8503a0bff6a1"
-REVISION="3"
+REVISION="4"
 ARCHITECTURES="x86_gcc2 !x86 x86_64"
 
 PATCHES="python-2.7.6.patchset"
@@ -41,9 +41,11 @@ REQUIRES="
 	lib:libreadline
 	lib:libsqlite3
 	lib:libz
+	lib:libffi
 	"
 BUILD_REQUIRES="
 	devel:libbz2
+	devel:libffi
 	devel:libncurses
 	devel:libssl
 	devel:libreadline
@@ -59,6 +61,7 @@ BUILD_PREREQUIRES="
 	cmd:ld
 	cmd:libtoolize
 	cmd:make
+	cmd:pkg_config
 	"
 
 SOURCE_DIR="Python-2.7.6"
@@ -76,7 +79,7 @@ BUILD()
 	libtoolize --force --copy --install
 	aclocal
 	autoconf
-	runConfigure ./configure \
+	runConfigure ./configure --with-system-ffi \
 		--enable-shared \
 		--enable-unicode=ucs4