anchor.diff:  , enableEXR ? !stdenv.isDarwin
   , openexr
   , ilmbase
  +, enableJPEG2000 ? true
  +, openjpeg
   , enableEigen ? true
   , eigen
   , enableOpenblas ? true
  
positive.code:     (opencvFlag "JPEG" enableJPEG)
      (opencvFlag "PNG" enablePNG)
      (opencvFlag "OPENEXR" enableEXR)
      (opencvFlag "CUDA" enableCuda)
      (opencvFlag "CUBLAS" enableCuda)
      (opencvFlag "TBB" enableTbb)
  
negative.code:     ++ lib.optional enableTIFF libtiff
      ++ lib.optional enableWebP libwebp
      ++ lib.optionals enableEXR [ openexr ilmbase ]
      ++ lib.optional enableJPEG2000 openjpeg
      ++ lib.optional enableFfmpeg ffmpeg
      ++ lib.optionals (enableFfmpeg && stdenv.isDarwin)
        [ VideoDecodeAcceleration bzip2 ]
  