anchor.diff:  returned file-path is relative to the link, not
   *DEFAULT-FILE-PATH-DEFAULTS*.
   
  -Signals an error if PATHSPEC is wild, or does not designate a
  -symbolic link."
  +Signals an error if PATHSPEC is not a symbolic link."
     ;; Note: the previous version tried much harder to provide a buffer
     ;; big enough to fit the link's name.  OTOH, NIX:READLINK stack
     ;; allocates on most lisps.
  
positive.code: :SYMBOLIC-LINK, :DIRECTORY, :PIPE, :SOCKET, :CHARACTER-DEVICE, and
  :BLOCK-DEVICE.
  If FOLLOW-SYMLINKS is non-NIL and PATHSPEC designates a broken symlink
  returns :BROKEN as second value.
  
  Signals an error if PATHSPEC is wild."
    (get-file-kind (merge-file-paths pathspec) follow-symlinks))
  
  (defun file-exists-p (pathspec &optional file-kind)
  
negative.code: :GROUP-READ, :GROUP-WRITE, :GROUP-EXEC, :OTHER-READ, :OTHER-WRITE,
  :OTHER-EXEC, :SET-USER-ID, :SET-GROUP-ID, and :STICKY.
  
  Both signal an error if PATHSPEC doesn't designate an existing file."
    (let ((mode (stat-mode (%sys-stat (file-path-namestring pathspec)))))
      (loop :for (name . value) :in +permissions+
            :when (plusp (logand mode value))
  