anchor.diff:  , enableEigen     ? false, eigen
   , enableOpenblas  ? false, openblas
   , enableCuda      ? false, cudatoolkit, gcc5
  +, enableTesseract ? false, tesseract, leptonica
   , AVFoundation, Cocoa, QTKit
   }:
   
  
positive.code:     sha256 = "11dsq8dwh1k6f7zglbc26xwsjw184ggf2531mhf7v77kd72k19fm";
    };
  
    vggFiles = fetchFromGitHub {
      owner  = "opencv";
      repo   = "opencv_3rdparty";
  
negative.code:           ln -s "${ippicv}" "${dir}/${name}"
          ''
      ) +
      (lib.optionalString buildContrib ''
        cmakeFlagsArray+=("-DOPENCV_EXTRA_MODULES_PATH=$NIX_BUILD_TOP/opencv_contrib")
      '');
  
  