Fix the _WCTYPE_T_DEFINED sentry for compatibility.

diff --git a/include/msvcrt/stdio.h b/include/msvcrt/stdio.h
index d5c9e11..df92ca6 100644
--- a/include/msvcrt/stdio.h
+++ b/include/msvcrt/stdio.h
@@ -129,10 +129,10 @@
 #endif
 #endif
 
-#ifndef MSVCRT_WCTYPE_T_DEFINED
-typedef MSVCRT(wchar_t) MSVCRT(wint_t);
-typedef MSVCRT(wchar_t) MSVCRT(wctype_t);
-#define MSVCRT_WCTYPE_T_DEFINED
+#ifndef _WCTYPE_T_DEFINED
+typedef unsigned short  MSVCRT(wint_t);
+typedef unsigned short  MSVCRT(wctype_t);
+#define _WCTYPE_T_DEFINED
 #endif
 
 #ifdef __cplusplus