diff --git a/libavformat/rtsp.c b/libavformat/rtsp.c
index 8ade1c64ec..57406a11d2 100644
--- a/libavformat/rtsp.c
+++ b/libavformat/rtsp.c
@@ -30,6 +30,7 @@
 #endif
 #include <strings.h>
 #include "network.h"
+#include "os_support.h"
 #include "rtsp.h"
 
 #include "rtpdec.h"