anchor.diff:  *DEFAULT-FILE-PATH-DEFAULTS*.
   
   SETF CURRENT-DIRECTORY changes the operating system's current
  -directory to the PATHSPEC.  An error is signalled if the PATHSPEC
  -is wild or does not designate a directory."
  +directory to the PATHSPEC.  An error is signalled if PATHSPEC
  +is not a directory."
     (let ((cwd (%sys-getcwd)))
       (if cwd
           (parse-file-path cwd :expand-user nil)
  
positive.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 is wild, or 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))
  
negative.code: returned file-path is relative to the link, not
  *DEFAULT-FILE-PATH-DEFAULTS*.
  
  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.
  