undef_method(mrb_state *mrb, struct RClass *c, mrb_sym a)
{
  mrb_method_t m;

  MRB_METHOD_FROM_PROC(m, NULL);
  mrb_define_method_raw(mrb, c, a, m);
}
undef_method(mrb_state *mrb, struct RClass *c, mrb_sym a)
{
  mrb_method_t m;

  MRB_METHOD_FROM_PROC(m, NULL);
  mrb_define_method_raw(mrb, c, a, m);
}