Using struct timeval requires sys/time.h, fixes compilation on some OSes

Patch by Dave Yeo, daveryeo at telus dot net

Originally committed as revision 22425 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rtpproto.c

@@ -36,6 +36,7 @@
 #if HAVE_SYS_SELECT_H
 #include <sys/select.h>
 #endif
+#include <sys/time.h>
 
 #define RTP_TX_BUF_SIZE  (64 * 1024)
 #define RTP_RX_BUF_SIZE  (128 * 1024)