diff --git a/sdk/lib/crt/startup/crtexe.c b/sdk/lib/crt/startup/crtexe.c
index 87da3dae394..fa20f4166e0 100644
--- a/sdk/lib/crt/startup/crtexe.c
+++ b/sdk/lib/crt/startup/crtexe.c
@@ -20,6 +20,9 @@
 #include <tchar.h>
 #include <sect_attribs.h>
 #include <locale.h>
+#ifdef _MBCS
+#include <mbstring.h>
+#endif
 
 #ifndef __winitenv
 extern wchar_t *** __MINGW_IMP_SYMBOL(__winitenv);