diff --git a/mingw-w64-headers/crt/_mingw_mac.h b/mingw-w64-headers/crt/_mingw_mac.h
index ca7c897..ee44fc3 100644
--- a/mingw-w64-headers/crt/_mingw_mac.h
+++ b/mingw-w64-headers/crt/_mingw_mac.h
@@ -301,6 +301,8 @@
 #  define __mingw_attribute_artificial
 #endif
 
+#define __MINGW_SELECTANY  __attribute__((__selectany__))
+
 #if _FORTIFY_SOURCE > 0 && __OPTIMIZE__ > 0 && __MINGW_GNUC_PREREQ(4, 1)
 #  if _FORTIFY_SOURCE > 1
 #    define __MINGW_FORTIFY_LEVEL 2
diff --git a/mingw-w64-headers/crt/locale.h b/mingw-w64-headers/crt/locale.h
index 6b1893b..9b695e3 100644
--- a/mingw-w64-headers/crt/locale.h
+++ b/mingw-w64-headers/crt/locale.h
@@ -103,6 +103,12 @@
   _CRTIMP wchar_t *__cdecl _wsetlocale(int _Category,const wchar_t *_Locale);
 #endif
 
+#ifdef __CHAR_UNSIGNED__
+/* Pull in the constructor from 'charmax.c'.  */
+extern int __mingw_initcharmax;
+__MINGW_SELECTANY int* __mingw_reference_charmax = &__mingw_initcharmax;
+#endif
+
 #ifdef __cplusplus
 }
 #endif