anchor.diff:  { lib, stdenv, fetchFromGitHub, fetchpatch, cmake, makeWrapper, openal, fluidsynth
   , soundfont-fluid, libGL, SDL2, bzip2, zlib, libjpeg, libsndfile, libvpx, mpg123
  -, game-music-emu, pkg-config, copyDesktopItems, makeDesktopItem }:
  +, game-music-emu, pkg-config, copyDesktopItems, makeDesktopItem, gtk3 }:
   
   let
     zmusic = stdenv.mkDerivation rec {
  
positive.code:     nativeBuildInputs = [ cmake makeWrapper pkg-config copyDesktopItems ];
      buildInputs = [
        SDL2
        libGL
        openal
        fluidsynth
        bzip2
        zlib
        libjpeg
        libsndfile
        libvpx
        mpg123
        game-music-emu
        zmusic
      ];
  
  
negative.code:     ];
  
      NIX_CFLAGS_LINK = "-lopenal -lfluidsynth";
  
      cmakeFlags = [ "-DDYN_GTK=OFF" ];
  
      desktopItems = [
        (makeDesktopItem {
  