anchor.diff:      ++ stdenv.lib.optional (qt != null) qt;
   
     prefixKey = "--prefix ";
  -  
  +
     configureFlags =
       [ "--dot dot" ]
       ++ stdenv.lib.optional (qt != null) "--with-doxywizard";
  
positive.code:   makeFlags = "MAN1DIR=share/man/man1";
  
    enableParallelBuilding = true;
    
    meta = {
      license = "GPLv2+";
      homepage = "http://doxygen.org/";
  
negative.code: { stdenv, fetchurl, perl, flex, bison, qt }:
  
  let
    name = "doxygen-1.7.4";
  in
  stdenv.mkDerivation {
    inherit name;
  
    src = fetchurl {
      url = "ftp://ftp.stack.nl/pub/users/dimitri/${name}.src.tar.gz";
  