make PixelFormat a typedef, fixes ffmpeg 1.1 compat

src/arch/ArchHooks/ArchHooks_Unix.cpp

@@ -21,6 +21,8 @@
 extern "C"
 {
 	#include <libavcodec/avcodec.h>
+	#undef PixelFormat
+	typedef AVPixelFormat PixelFormat;
 }
 #endif
 

src/arch/MovieTexture/MovieTexture_FFMpeg.cpp

@@ -16,6 +16,8 @@ namespace avcodec
 		#include <libavformat/avformat.h>
 		#include <libswscale/swscale.h>
 		#include <libavutil/pixdesc.h>
+		#undef PixelFormat
+		typedef AVPixelFormat PixelFormat;
 	}
 };