hb_set_union (hb_set_t       *set,
	      const hb_set_t *other)
{
  /* Immutible-safe. */
  set->union_ (*other);
}
hb_set_union (hb_set_t       *set,
	      const hb_set_t *other)
{
   
  set->union_ (*other);
}