lib.filesystem.pathType: Use new builtins.readFileType if available

      pathType /some/file.nix

      => "regular"

  */

  pathType = path:

  pathType =

    builtins.readFileType or

    # Nix <2.14 compatibility shim

    (path:

      if ! pathExists path

      # Fail irrecoverably to mimic the historic behavior of this function and

      # the new builtins.readFileType

      # "directory", since we know the filesystem root can't be anything else.

      else if dirOf path == path

      then "directory"

    else (readDir (dirOf path)).${baseNameOf path};

      else (readDir (dirOf path)).${baseNameOf path}

    );

  /*

    Whether a path exists and is a directory.