anchor.diff:  
   netmask_to_wildcard(ipv4, Mask) -> ((1 bsl ?MAXBITS_IPV4) - 1) bxor Mask;
   netmask_to_wildcard(ipv6, Mask) -> ((1 bsl ?MAXBITS_IPV6) - 1) bxor Mask.
  +
  +subconfigdir_fold(_File, {error, _Err}=Acc) ->
  +    Acc;
  +subconfigdir_fold(File, {ok, GCp, Csp}=Acc) ->
  +    case is_file(File) of
  +        true ->
  +            error_logger:info_msg("Yaws: Using subconfig file ~s~n", [File]),
  +            case file:open(File, [read]) of
  +                {ok, FD1} ->
  +                    R = (catch fload(FD1,
  +                                     globals,
  +                                     GCp,
  +                                     undefined,
  +                                     Csp,
  +                                     1,
  +                                     io:get_line(FD1, ''))),
  +                    ?Debug("FLOAD: ~p", [R]),
  +                    R;
  +                _ ->
  +                    {error, "Can't open config file " ++ File}
  +            end;
  +        false ->
  +            %% Ignore subdirectories
  +            Acc
  +    end.
  
positive.code:                                       fun(N) ->
                                                filename:absname(N, Dir)
                                        end, Names),
                              case lists:foldl(
                                     fun(File, Acc) ->
                                             case Acc of
                                                 {error, _Err} ->
                                                     Acc;
                                                 {ok, GCp, Csp} ->
                                                     case is_file(File) of
                                                         true ->
                                                             error_logger:info_msg(
                                                               "Yaws: Using subconfig file ~s~n",
                                                               [File]),
                                                             case file:open(File, [read]) of
                                                                 {ok, FD1} ->
                                                                     R = (catch fload(FD1,
                                                                                      globals,
                                                                                      GCp,
                                                                                      undefined,
                                                                                      Csp,
                                                                                      1,
                                                                                      io:get_line(FD1, ''))),
                                                                     ?Debug("FLOAD: ~p", [R]),
                                                                     R;
                                                                 _ ->
                                                                     {error, "Can't open config file " ++
                                                                          File}
                                                             end;
                                                         false ->
                                                             %% Ignore subdirectories
                                                             Acc
                                                     end
                                             end
                                     end, {ok, GC, Cs}, Paths) of
                                  {ok, GC1, Cs1} ->
                                      fload(FD, globals, GC1, C, Cs1, Lno+1, Next);
                                  Err ->
                                      Err
                              end;
                          {error, Error} ->
                              {error, ?F("Directory ~s is not readable: ~s", [Name, Error])}
                      end;
                  false ->
                      {error, ?F("Expect directory at line ~w (subconfdir: ~s)", [Lno, Dir])}
              end;
  
          ["trace", '=', Bstr] when GC#gconf.trace == false ->
  
negative.code:                 {ok, [Hd|_Tl]=PList} when is_atom(Hd); is_tuple(Hd) ->
                      %% create new safe proplist of desired options
                      {ok, proplists_int_copy([], PList, [fullsweep_after,
                                                          min_heap_size,
                                                          min_bin_vheap_size])};
                  _ ->
                      {error, "Expect undefined or proplist"}
              end;
  