return nil
}

func (f *buildvcsFlag) String() string { return string(*f) }

// fileExtSplit expects a filename and returns the name
// and ext (without the dot). If the file has no
// extension, ext will be empty.
func fileExtSplit(file string) (name, ext string) {
	dotExt := filepath.Ext(file)
	name = file[:len(file)-len(dotExt)]
	if dotExt != "" {
		ext = dotExt[1:]

	// For example, defs_linux_amd64.h becomes defs_GOOS_GOARCH.h.
	_goos_goarch := "_" + cfg.Goos + "_" + cfg.Goarch
	_goos := "_" + cfg.Goos
	_goarch := "_" + cfg.Goarch
	for _, file := range p.HFiles {
		name, ext := fileExtSplit(file)
		switch {
		case strings.HasSuffix(name, _goos_goarch):
			targ := file[:len(name)-len(_goos_goarch)] + "_GOOS_GOARCH." + ext