anchor.diff:  , libraw1394
   , libtiff
   , libwebp
  -, mesa
  +, opengl-dummy
   #, nvidia-cuda-toolkit
   #, openexr
   , pango
  
positive.code:     # WITH_OPENCL_SVM
      #"-DWITH_OPENEXR=${boolOn (openexr != null)}"
      /**/"-DWITH_OPENEXR=OFF"
      "-DWITH_OPENGL=${boolOn (mesa != null)}"
      # WITH_OPENMP
      # WITH_OPENNI
      # WITH_OPENNI2
  
negative.code:     libraw1394
      libtiff
      libwebp
      #openexr
      opengl-dummy
      pango
      #python2Packages.numpy
      #python2Packages.python
  