anchor.diff:    meta = with stdenv.lib; {
       homepage = "https://github.com/coelckers/gzdoom";
       description = "A Doom source port based on ZDoom. It features an OpenGL renderer and lots of new features";
  -    # Doom source license, MAME license
  -    license = licenses.unfreeRedistributable;
  +    license = licenses.gpl3;
       platforms = platforms.linux;
       maintainers = with maintainers; [ lassulus ];
     };
  
positive.code:     sed -i \
        -e "s@/usr/share/sounds/sf2/@${soundfont-fluid}/share/soundfonts/@g" \
        -e "s@FluidR3_GM.sf2@FluidR3_GM2-2.sf2@g" \
        src/sound/music_fluidsynth_mididevice.cpp
    '';
  
    installPhase = ''
  
negative.code: 
  stdenv.mkDerivation rec {
    name = "gzdoom-${version}";
    version = "3.0.1";
  
    src = fetchFromGitHub {
      owner = "coelckers";
      repo = "gzdoom";
      rev = "g${version}";
      sha256 = "0s0hl7pa2gr3cm884q7np5naybhv4hqhbfd3s45a8hdf72n6c9cm";
    };
  
    nativeBuildInputs = [ cmake makeWrapper ];
  