anchor.diff:  { lib, stdenv
   , fetchurl, fetchFromGitHub, fetchpatch
   , cmake, pkgconfig, unzip, zlib, pcre, hdf5
  -, caffe, glog, boost, google-gflags, protobuf
  +, glog, boost, google-gflags, protobuf
   , config
   
   , enableJPEG      ? true, libjpeg
  
positive.code: 
    buildInputs =
         [ zlib pcre hdf5 glog boost google-gflags protobuf ]
      ++ lib.optional (!stdenv.isDarwin) caffe
      ++ lib.optional enablePython pythonPackages.python
      ++ lib.optional enableGtk2 gtk2
      ++ lib.optional enableGtk3 gtk3
  
negative.code:     "-DBUILD_PROTOBUF=OFF"
      "-DPROTOBUF_UPDATE_FILES=ON"
      "-DOPENCV_ENABLE_NONFREE=${printEnabled enableUnfree}"
      "-DBUILD_TESTS=OFF"
      "-DBUILD_PERF_TESTS=OFF"
      (opencvFlag "IPP" enableIpp)
      (opencvFlag "TIFF" enableTIFF)
      (opencvFlag "JASPER" enableJPEG2K)
  