Use full path for #includes from another directory.

Originally committed as revision 13098 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/avfilter.c

@@ -19,8 +19,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "libavcodec/imgconvert.h"
 #include "avfilter.h"
-#include "imgconvert.h"
 
 /** list of registered filters */
 struct FilterList