delete

static VALUE
dir_s_rmdir(VALUE obj, VALUE dir)
{
    const char *p;
    int r;

    dir = check_dirname(dir);
    p = RSTRING_PTR(dir);
    r = (int)(VALUE)rb_thread_call_without_gvl(nogvl_rmdir, (void *)p, RUBY_UBF_IO, 0);
    if (r < 0)
        rb_sys_fail_path(dir);

    return INT2FIX(0);
}