extern void ** htab_find_slot_with_hash (htab_t, const void *,
hashval_t, enum insert_option);
extern void htab_clear_slot (htab_t, void **);
-extern void htab_remove_elt (htab_t, void *);
-extern void htab_remove_elt_with_hash (htab_t, void *, hashval_t);
+extern void htab_remove_elt (htab_t, const void *);
+extern void htab_remove_elt_with_hash (htab_t, const void *, hashval_t);
extern void htab_traverse (htab_t, htab_trav, void *);
extern void htab_traverse_noresize (htab_t, htab_trav, void *);