diff --git a/libavformat/os_support.c b/libavformat/os_support.c
index 30581ed7c2..2d8a90346a 100644
--- a/libavformat/os_support.c
+++ b/libavformat/os_support.c
@@ -29,6 +29,9 @@
 
 #if defined(_WIN32) && !defined(__MINGW32CE__)
 #undef open
+#undef lseek
+#undef stat
+#undef fstat
 #include <fcntl.h>
 #include <io.h>
 #include <windows.h>
diff --git a/libavformat/os_support.h b/libavformat/os_support.h
index c5d3ab4b33..39d4cb6519 100644
--- a/libavformat/os_support.h
+++ b/libavformat/os_support.h
@@ -31,7 +31,7 @@
 
 #include <sys/stat.h>
 
-#if defined(__MINGW32__) && !defined(__MINGW32CE__)
+#if defined(_WIN32) && !defined(__MINGW32CE__)
 #  include <fcntl.h>
 #  define lseek(f,p,w) _lseeki64((f), (p), (w))
 #  define stat _stati64