anchor.diff: -{ stdenv, mkDerivation, fetchFromGitHub, cmake, qtbase, alsaLib, makeDesktopItem }:
  +{ stdenv, mkDerivation, fetchFromGitHub, cmake, qtbase, alsaLib, makeDesktopItem, libjack2 }:
   
   let
     desktopItem = makeDesktopItem rec {
  
positive.code:   dontFixCmake = true;
  
    nativeBuildInputs = [ cmake ];
    buildInputs = [ qtbase alsaLib ];
  
    meta = with stdenv.lib; {
      description = "Multi-platform software synthesiser emulating Roland MT-32, CM-32L, CM-64 and LAPC-I devices";
  
negative.code:     categories = "Audio;AudioVideo;";
    };
  in mkDerivation rec {
    version = "2.4.1";
    pname = "munt";
  
    src = fetchFromGitHub {
      owner = pname;
      repo = pname;
      rev = with stdenv.lib.versions; "libmt32emu_${major version}_${minor version}_${patch version}";
      sha256 = "0bszhkbz24hhx32f973l6h5lkyn4lxhqrckiwmv765d1sba8n5bk";
    };
  
    postInstall = ''
  