func subdir() (pkgpath string, underGoRoot bool, err error) {
	cwd, err := os.Getwd()
	if err != nil {
		return "", false, err
	}
	cwd, err = filepath.EvalSymlinks(cwd)
	if err != nil {
		log.Fatal(err)
	}
	goroot, err := filepath.EvalSymlinks(runtime.GOROOT())
	if err != nil {
		return "", false, err
	}
	if strings.HasPrefix(cwd, goroot) {
		subdir, err := filepath.Rel(goroot, cwd)
		if err != nil {

set, and reparse points that are not symlinks, Unix sockets, or dedup files now
always have [`os.ModeIrregular`](/pkg/os#ModeIrregular) set. As a result of these changes,
[`filepath.EvalSymlinks`](/pkg/path/filepath#EvalSymlinks) no longer evaluates
mount points, which was a source of many inconsistencies and bugs.
At previous versions (`winsymlink=0`), mount points are treated as symlinks,

	result := make(map[string]string)
	err := filepath.Walk("/dev/disk/by-uuid/",
		func(path string, info os.FileInfo, err error) error {
			if err != nil {
				return err
			}
			realPath, err := filepath.EvalSymlinks(path)
			if err != nil {
				return err
			}
			result[realPath] = strings.TrimPrefix(path, "/dev/disk/by-uuid/")
			return nil
		})
	if err != nil {
		return nil, err
	}
	return result, nil
}