eval.c:3747
static VALUE
rb_obj_respond_to(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    VALUE mid, priv;
    ID id;

    rb_scan_args(argc, argv, "11", &mid, &priv);
    id = rb_to_id(mid);
    if (rb_method_boundp(CLASS_OF(obj), id, !RTEST(priv))) {
	return Qtrue;
    }
    return Qfalse;
}
