anchor.diff:        "-DPYTHON_LIBPATH=${python}/lib"
         "-DPYTHON_INCLUDE_DIR=${python}/include/python${python.majorVersion}m"
         "-DPYTHON_VERSION=${python.majorVersion}"
  -    ] ++ stdenv.lib.optional jackaudioSupport "-DWITH_JACK=ON";
  +    ]
  +    ++ optional jackaudioSupport "-DWITH_JACK=ON";
   
     NIX_CFLAGS_COMPILE = "-I${ilmbase}/include/OpenEXR -I${python}/include/${python.libPrefix}m";
   
  
positive.code:   buildInputs =
      [ SDL boost cmake ffmpeg gettext glew ilmbase libXi
        libjpeg libpng libsamplerate libsndfile libtiff mesa openal
        opencolorio openexr openimageio openjpeg python zlib
      ] ++ stdenv.lib.optional jackaudioSupport jackaudio;
  
    postUnpack =
      ''
  
negative.code:   cmakeFlags =
      [ "-DOPENEXR_INC=${openexr}/include/OpenEXR"
        "-DWITH_OPENCOLLADA=OFF"
        "-DWITH_MOD_OCEANSIM=ON"
        "-DWITH_CODEC_FFMPEG=ON"
        "-DWITH_CODEC_SNDFILE=ON"
        "-DWITH_INSTALL_PORTABLE=OFF"
  