diff --git a/mingw-w64-headers/crt/locale.h b/mingw-w64-headers/crt/locale.h
index 336429f..068f456 100644
--- a/mingw-w64-headers/crt/locale.h
+++ b/mingw-w64-headers/crt/locale.h
@@ -86,6 +86,8 @@
   _locale_t __cdecl __create_locale(int _Category,const char *_Locale);
   void __cdecl __free_locale(_locale_t _Locale);
 
+  _CRTIMP unsigned int __cdecl ___lc_codepage_func(void);
+
 #ifndef _WLOCALE_DEFINED
 #define _WLOCALE_DEFINED
   _CRTIMP wchar_t *__cdecl _wsetlocale(int _Category,const wchar_t *_Locale);