bin, args := flattenCmdline(cmdline)
	cmd := exec.Command(bin, args...)
	if filepath.IsAbs(dir) {
		setDir(cmd, dir)
	} else {
		setDir(cmd, filepath.Join(goroot, dir))
	}
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	if vflag > 1 {
		errprintf("%s\n", strings.Join(cmd.Args, " "))
	}
	return cmd
}