Remove unnecessary system include path from pkg-config files.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@11247 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

configure

@@ -2081,7 +2081,7 @@ Version: $version
 Requires: $requires
 Conflicts:
 Libs: -L\${libdir} $libs
-Cflags: -I\${includedir} -I\${includedir}/$include
+Cflags: -I\${includedir}/$include
 EOF
 }