anchor.diff:      libusb1
       sane-backends
       dbus
  +    file
  +    ghostscript
       net_snmp
       openssl
  +    perl
       zlib
     ];
   
  
positive.code:       --with-systraydir=$out/xdg/autostart
        --with-mimedir=$out/etc/cups
        --enable-policykit
        --disable-qt4
        ${stdenv.lib.optionalString withQt5 "--enable-qt5"}
      "
  
negative.code:       hplip_confdir=$out/etc/hp
        hplip_statedir=$out/var/lib/hp
      "
  
      # Prevent 'ppdc: Unable to find include file "<font.defs>"' which prevent
      # generation of '*.ppd' files.
      # This seems to be a 'ppdc' issue when the tool is run in a hermetic sandbox.
      # Could not find how to fix the problem in 'ppdc' so this is a workaround.
      export CUPS_DATADIR="${cups}/share/cups"
    '';
  
    enableParallelBuilding = true;
  
    #
    # Running `hp-diagnose_plugin -g` can be used to diagnose
    # issues with plugins.
    #
    postInstall = stdenv.lib.optionalString withPlugin ''
      sh ${plugin} --noexec --keep
      cd plugin_tmp
  