diff --git a/ffmpeg.c b/ffmpeg.c
index 42f0b218d4..8ea5b3a6a0 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -33,6 +33,7 @@
 #include "opt.h"
 #include "fifo.h"
 #include "avstring.h"
+#include "os_support.h"
 
 #if !defined(HAVE_GETRUSAGE) && defined(HAVE_GETPROCESSTIMES)
 #include <windows.h>
diff --git a/libavformat/file.c b/libavformat/file.c
index f61130694f..6285c1bba2 100644
--- a/libavformat/file.c
+++ b/libavformat/file.c
@@ -24,6 +24,7 @@
 #include <unistd.h>
 #include <sys/time.h>
 #include <stdlib.h>
+#include "os_support.h"
 
 
 /* standard file protocol */
diff --git a/libavformat/http.c b/libavformat/http.c
index 5bfd736885..240840a271 100644
--- a/libavformat/http.c
+++ b/libavformat/http.c
@@ -21,6 +21,7 @@
 #include "avformat.h"
 #include <unistd.h>
 #include "network.h"
+#include "os_support.h"
 
 #include "base64.h"
 #include "avstring.h"