Let MB_CUR_LEN lookup the actual value.

* instead of yielding 1, MB_CUR_LEN now looks up the correct
  value in the ctype data provided by the locale backend

headers/private/libroot/locale/LocaleBackend.h

@@ -31,6 +31,8 @@ struct LocaleCtypeDataBridge {
 	const int*				posixToUpperMap;
 
 	LocaleCtypeDataBridge();
+
+	void setMbCurMax(unsigned short mbCurMax);
 };