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