anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "furnace";
  -  version = "0.5.6";
  +  version = "0.5.8";
   
     src = fetchFromGitHub {
       owner = "tildearrow";
       repo = "furnace";
       rev = "v${version}";
       fetchSubmodules = true;
  -    sha256 = "sha256-BcaPQuDFkAaxFQKwoI6xdSWcyHo5VsqZcwf++JISqRs=";
  +    sha256 = "103ymd3wa1sfsr6qg15vpcs53j350i7zidv3azlf7cynk6k28xim";
     };
  -
  -  patches = [
  -    (fetchpatch {
  -      name = "0001-furnace-fix-wrong-include-path.patch";
  -      url = "https://github.com/tildearrow/furnace/commit/456db22f9d9f0ed40d74fe50dde492e69e901fcc.patch";
  -      sha256 = "17ikb1z9ldm7kdj00m4swsrq1qx94vlzhc6h020x3ryzwnglc8d3";
  -    })
  -  ];
   
     postPatch = ''
       # rtmidi is not used yet
  
positive.code:     cp -r ../demos $out/share/furnace/
    '';
  
    passthru.updateScript = nix-update-script {
      attrPath = pname;
    };
  
    meta = with lib; {
  
negative.code: { stdenv
  , lib
  , gitUpdater
  , testVersion
  , furnace
  , fetchFromGitHub
  , cmake
  , pkg-config
  , makeWrapper
  