declare and make hidden more internal locale functions

src/internal/locale_impl.h

@@ -23,7 +23,9 @@ hidden const struct __locale_map *__get_locale(int, const char *);
 hidden const char *__mo_lookup(const void *, size_t, const char *);
 hidden const char *__lctrans(const char *, const struct __locale_map *);
 hidden const char *__lctrans_cur(const char *);
+hidden const char *__lctrans_impl(const char *, const struct __locale_map *);
 hidden int __loc_is_allocated(locale_t);
+hidden char *__gettextdomain(void);
 
 #define LCTRANS(msg, lc, loc) __lctrans(msg, (loc)->cat[(lc)])
 #define LCTRANS_CUR(msg) __lctrans_cur(msg)