anchor.diff:  rename_equivalent(Options) ->
     rename_equivalent(Options, []).
   
  -rename_equivalent([quiet|Rest], Acc) ->
  +rename_equivalent([{quiet, true}|Rest], Acc) ->
     case proplists:is_defined(verbosity, Rest ++ Acc) of
       true -> opt_error("'--verbosity' specified together with '--quiet'");
       false ->
  
positive.code:       opt_error(Error, [?ldebug - 1])
    end,
    finalize(NewRest, [{verbosity, Verbosity}|Acc]);
  finalize([{Key, Value}|Rest], Acc) when Key =:= pa; Key =:=pz ->
    PathAdd =
      case Key of
        pa -> fun code:add_patha/1;
  
negative.code:       case atom_to_list(Name) of
          "-" ++ Rest -> cl_usage(list_to_atom(Rest));
          _ ->
            Msg = "Invalid option name (given as argument to --help): '~w'",
            opt_error(Msg, [Name])
        end;
      Tuple ->
        getopt:usage(getopt_spec([Tuple]), "./concuerror"),
  