mrb_class_defined_under(mrb_state *mrb, struct RClass *outer, const char *name)
{
  mrb_sym sym = mrb_intern_check_cstr(mrb, name);
  if (!sym) return FALSE;
  return mrb_const_defined_at(mrb, mrb_obj_value(outer), sym);
}
mrb_class_defined_under(mrb_state *mrb, struct RClass *outer, const char *name)
{
  mrb_sym sym = mrb_intern_check_cstr(mrb, name);
  if (!sym) return FALSE;
  return mrb_const_defined_at(mrb, mrb_obj_value(outer), sym);
}