diff --git a/mrbgems/mruby-io/test/mruby_io_test.c b/mrbgems/mruby-io/test/mruby_io_test.c
index 36f734382..71239a827 100644
--- a/mrbgems/mruby-io/test/mruby_io_test.c
+++ b/mrbgems/mruby-io/test/mruby_io_test.c
@@ -19,6 +19,8 @@ typedef int mode_t;
 #define close _close
 
 #ifdef _MSC_VER
+#include <sys/stat.h>
+
 static int
 mkstemp(char *p)
 {