anchor.diff:    meta = {
       description = "Open Computer Vision Library with more than 500 algorithms";
       homepage = http://opencv.org/;
  -    license = stdenv.lib.licenses.bsd3;
  +    license = with stdenv.lib.licenses; if enableUnfree then unfree else bsd3;
       maintainers = with stdenv.lib.maintainers; [viric mdaiter basvandijk];
       platforms = with stdenv.lib.platforms; linux ++ darwin;
     };
  
positive.code: 
  , enableCuda      ? (config.cudaSupport or false), cudatoolkit
  
  , enableIpp       ? false
  , enableContrib   ? false
  , enablePython    ? false, pythonPackages
  
negative.code:     "-DWITH_OPENMP=ON"
      "-DBUILD_PROTOBUF=OFF"
      "-DPROTOBUF_UPDATE_FILES=ON"
      "-DOPENCV_ENABLE_NONFREE=${printEnabled enableUnfree}"
      (opencvFlag "IPP" enableIpp)
      (opencvFlag "TIFF" enableTIFF)
      (opencvFlag "JASPER" enableJPEG2K)
  