diff --git a/libavformat/sapenc.c b/libavformat/sapenc.c
index 7c56ddbe39..9c576cfd94 100644
--- a/libavformat/sapenc.c
+++ b/libavformat/sapenc.c
@@ -25,6 +25,7 @@
 #include "libavutil/intreadwrite.h"
 #include "internal.h"
 #include "network.h"
+#include "os_support.h"
 #include "rtpenc_chain.h"
 
 struct SAPState {