mrb_define_alias_id(mrb_state *mrb, struct RClass *klass, mrb_sym a, mrb_sym b)
{
  mrb_alias_method(mrb, klass, a, b);
}
mrb_define_alias_id(mrb_state *mrb, struct RClass *klass, mrb_sym a, mrb_sym b)
{
  mrb_alias_method(mrb, klass, a, b);
}