diff --git a/libavformat/udp.c b/libavformat/udp.c
index 1730130730..6a2e642fe3 100644
--- a/libavformat/udp.c
+++ b/libavformat/udp.c
@@ -24,6 +24,7 @@
  * UDP protocol
  */
 
+#define _BSD_SOURCE     /* Needed for using struct ip_mreq with recent glibc */
 #include "avformat.h"
 #include <unistd.h>
 #include "network.h"