return keep
}

const (
	CheckExit = 1 << iota
	ShowOutput
	Background
)

var outputLock sync.Mutex

// run is like runEnv with no additional environment.
func run(dir string, mode int, cmd ...string) string {
	return runEnv(dir, mode, nil, cmd...)
}

// runEnv runs the command line cmd in dir with additional environment env.
// If mode has ShowOutput set and Background unset, run passes cmd's output to

	}
	if vflag > 0 {
		cmd = append(cmd, "-v")
	}
	if tool := os.Getenv("GOBOOTSTRAP_TOOLEXEC"); tool != "" {
		cmd = append(cmd, "-toolexec="+tool)
	}
	cmd = append(cmd, "bootstrap/cmd/...")
	run(base, ShowOutput|CheckExit, cmd...)

	// Copy binaries into tool binary directory.
	for _, name := range bootstrapDirs {
		if !strings.HasPrefix(name, "cmd/") {
			continue
		}
		name = name[len("cmd/"):]