# readlink(1) is not available as standard on Solaris 10.
    readLink=`which readlink`
    if [ ! `expr "$readLink" : '\([^ ]*\)'` = "no" ]; then
      if $darwin ; then
        javaHome="`dirname \"$javaExecutable\"`"
        javaExecutable="`cd \"$javaHome\" && pwd -P`/javac"
      else
        javaExecutable="`readlink -f \"$javaExecutable\"`"
      fi

    # readlink(1) is not available as standard on Solaris 10.
    readLink=$(which readlink)
    if [ ! "$(expr "$readLink" : '\([^ ]*\)')" = "no" ]; then
      if $darwin; then
        javaHome="$(dirname "$javaExecutable")"
        javaExecutable="$(cd "$javaHome" && pwd -P)/javac"
      else
        javaExecutable="$(readlink -f "$javaExecutable")"
      fi

and other reparse points with non-default [`os.ModeType`](/pkg/os#ModeType) bits
(such as [`os.ModeDir`](/pkg/os#ModeDir)) do not have the `ModeIrregular` bit set.

Go 1.23 changed [`os.Readlink`](/pkg/os#Readlink) and [`filepath.EvalSymlinks`](/pkg/path/filepath#EvalSymlinks)
to avoid trying to normalize volumes to drive letters, which was not always even possible.
This behavior is controlled by the `winreadlinkvolume` setting.

			open(path, flags, mode, callback) { callback(enosys()); },
			read(fd, buffer, offset, length, position, callback) { callback(enosys()); },
			readdir(path, callback) { callback(enosys()); },
			readlink(path, callback) { callback(enosys()); },
			rename(from, to, callback) { callback(enosys()); },
			rmdir(path, callback) { callback(enosys()); },
			stat(path, callback) { callback(enosys()); },

			return nil
		}
		info, err := d.Info()
		if err != nil {
			return err
		}
		linkTarget := ""
		if typ := d.Type(); typ == fs.ModeSymlink {
			var err error
			linkTarget, err = fs.ReadLink(fsys, name)
			if err != nil {
				return err
			}
		} else if !typ.IsRegular() && typ != fs.ModeDir {
			return errors.New("tar: cannot add non-regular file")
		}
		h, err := FileInfoHeader(info, linkTarget)