anchor.diff:    ];
   
     buildInputs = [
  +    fftw
       fmt_8
       libsndfile
  +    rtmidi
       SDL2
       zlib
     ] ++ lib.optionals withJACK [
  
positive.code:     };
      tests.version = testers.testVersion {
        package = furnace;
        # The command always exits with code 1
        command = "(furnace --version || [ $? -eq 1 ])";
      };
    };
  
  
negative.code: 
    cmakeFlags = [
      "-DBUILD_GUI=${if withGUI then "ON" else "OFF"}"
      "-DSYSTEM_FFTW=ON"
      "-DSYSTEM_FMT=ON"
      "-DSYSTEM_LIBSNDFILE=ON"
      "-DSYSTEM_RTMIDI=ON"
      "-DSYSTEM_SDL2=ON"
      "-DSYSTEM_ZLIB=ON"
      "-DWITH_JACK=${if withJACK then "ON" else "OFF"}"
      "-DWARNINGS_ARE_ERRORS=ON"
    ];
  