anchor.diff:        --prefix PATH : "${djvulibre}/bin" \
         --prefix PATH : "${poppler_utils}/bin" \
         --prefix PATH : "${ghostscript}/bin" \
  -      --prefix PATH : "${unpaper}/bin"
  +      --prefix PATH : "${unpaper}/bin" \
  +      --prefix PATH : "${pdftk}/bin"
     '';
   
     enableParallelBuilding = true;
  
positive.code:   outputs = [ "out" "man" ];
  
    checkInputs = [
      xvfb_run
      hicolor-icon-theme
      imagemagick
      libtiff
      djvulibre
      poppler_utils
      ghostscript
      file
      pdftk
      unpaper
    ];
  
    checkPhase = ''
  
negative.code:     description = "A GUI to produce PDFs or DjVus from scanned documents";
      homepage = http://gscan2pdf.sourceforge.net/;
      license = licenses.gpl3;
      maintainers = with maintainers; [ pacien ];
    };
  }
  