anchor.diff:  DEFAULT:            Thunk called if ARGUMENTS is empty.
   UNDEFINED-ARGUMENT: Thunk called if an undefined option is present in
                       the ARGUMENTS.
  +RETURN:             NIL on success, status code when early exit is requested.
   "
     (handler-case
         (flet ((process-arguments ()
  
positive.code:                   nil)
                   (default
                    (funcall default)))))
          (if *debug*
              (process-arguments)
              (handler-case
                  (process-arguments)
  
negative.code: otherwise we fallback to *PROGRAM-NAME*.")
  
  
  (defvar *debug-options* nil
    "Errors break into the debugger.")
  
  ;;;
  