Include avc.h from avc.c: It contains several prototypes.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@22098 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavformat/avc.c

@@ -22,6 +22,7 @@
 #include "libavutil/intreadwrite.h"
 #include "avformat.h"
 #include "avio.h"
+#include "avc.h"
 
 static const uint8_t *ff_avc_find_startcode_internal(const uint8_t *p, const uint8_t *end)
 {