anchor.diff:        openvdb
       ]
       else [
  -      pugixml llvmPackages.openmp SDL Cocoa CoreGraphics ForceFeedback OpenAL OpenGL
  +      llvmPackages.openmp SDL Cocoa CoreGraphics ForceFeedback OpenAL OpenGL
       ])
       ++ optional jackaudioSupport libjack2
       ++ optional cudaSupport cudatoolkit
  
positive.code:       alembic
        (opensubdiv.override { inherit cudaSupport; })
        tbb
        makeWrapper
        embree
        gmp
      ]
      ++ (if (!stdenv.isDarwin) then [
        libXi libX11 libXext libXrender
  
negative.code: 
    patches = lib.optional stdenv.isDarwin ./darwin.patch;
  
    nativeBuildInputs = [ cmake makeWrapper ] ++ optional cudaSupport addOpenGLRunpath;
    buildInputs =
      [ boost ffmpeg gettext glew ilmbase
        freetype libjpeg libpng libsamplerate libsndfile libtiff
  