diff --git a/include/sys/types.h b/include/sys/types.h
index 510f512b..03dd1041 100644
--- a/include/sys/types.h
+++ b/include/sys/types.h
@@ -138,6 +138,15 @@ typedef long ssize_t;
 typedef unsigned uid_t;
 #endif
 
+#ifndef __WCHAR_T
+#define __WCHAR_T
+#ifndef __MES_WCHAR_T
+#define __MES_WCHAR_T
+#undef wchar_t
+typedef int wchar_t;
+#endif
+#endif
+
 #endif // ! SYSTEM_LIBC
 
 #endif // __MES_SYS_TYPES_H
diff --git a/lib/stdlib/mbstowcs.c b/lib/stdlib/mbstowcs.c
index a948544d..0820c1ef 100644
--- a/lib/stdlib/mbstowcs.c
+++ b/lib/stdlib/mbstowcs.c
@@ -22,9 +22,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-#if !__MESC__
-typedef char wchar_t[];
-
 size_t
 mbstowcs (wchar_t * wstring, char const *string, size_t size)
 {
@@ -35,4 +32,3 @@ mbstowcs (wchar_t * wstring, char const *string, size_t size)
   strcpy (wstring, string);
   return strlen (string);
 }
-#endif