Explicitly include rtp.h (needed for rtp_get_payload_type())

Originally committed as revision 10863 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/sdp.c

@@ -20,6 +20,7 @@
 
 #include "avstring.h"
 #include "avformat.h"
+#include "rtp.h"
 
 #ifdef CONFIG_RTP_MUXER
 #define MAX_EXTRADATA_SIZE ((INT_MAX - 10) / 2)