anchor.diff:    propagatedBuildInputs = [
       /* Python is used at run-time to execute scripts, e.g.
          those in the "Effects" menu. */
  -    pyxml
       pythonPackages.lxml
       pythonPackages.python
  +    pythonPackages.pyxml
     ];
   
     buildInputs = [
  
positive.code: , poppler
  , popt
  , pythonPackages
  , pyxml
  , xorg
  , zlib
  
  
negative.code:   /* Make sure PyXML modules can be found at run-time. */ ''
      for i in "$out/bin/"* ; do
        wrapProgram "$i" \
          --prefix PYTHONPATH : "$(toPythonPath ${pythonPackages.pyxml})" \
          --prefix PYTHONPATH : "$(toPythonPath ${pythonPackages.lxml})" \
          --prefix PATH : ${pythonPackages.python}/bin
      done
  