anchor.diff:      ++ lib.optional tiffSupport libtiff
       ++ lib.optional gdalSupport gdal
       ++ lib.optional curlSupport curl
  -    ++ lib.optional colladaSupport opencollada
  +    ++ lib.optional colladaSupport collada-dom
       ++ lib.optional opencascadeSupport opencascade
       ++ lib.optional ffmpegSupport ffmpeg
       ++ lib.optional nvttSupport nvidia-texture-tools
  
positive.code:     ++ lib.optional lasSupport libLAS
      ++ lib.optional luaSupport lua
      ++ lib.optional sdlSupport SDL2
      ++ lib.optionals restSupport [ asio boost ]
      ++ lib.optionals withExamples [ fltk wxGTK ]
      ++ lib.optionals stdenv.isDarwin [ AGL Carbon Cocoa Foundation ]
    ;
  
    cmakeFlags = lib.optional (!withApps) "-DBUILD_OSG_APPLICATIONS=OFF" ++ lib.optional withExamples "-DBUILD_OSG_EXAMPLES=ON";
  
negative.code:   lasSupport ? false, libLAS,
    luaSupport ? false, lua,
    sdlSupport ? false, SDL2,
    restSupport ? false, asio,
    withApps ? false,
    withExamples ? false, fltk, wxGTK,
  }:
  