anchor.diff:  { lib, stdenv, fetchurl, makeWrapper
   , pkg-config, intltool
  -, perl, gettext, libX11, libXext, libXi, libXt
  +, perl, perlPackages, gettext, libX11, libXext, libXi, libXt
   , libXft, libXinerama, libXrandr, libXxf86vm, libGL, libGLU, gle
   , gtk2, gdk-pixbuf, gdk-pixbuf-xlib, libxml2, pam
   , systemd, coreutils
  
positive.code:     perl gettext libX11 libXext libXi libXt
      libXft libXinerama libXrandr libXxf86vm libGL libGLU gle
      gtk2 gdk-pixbuf gdk-pixbuf-xlib libxml2 pam
    ] ++ lib.optional withSystemd systemd;
  
    preConfigure = ''
  
negative.code:     for bin in $out/bin/*; do
        wrapProgram "$bin" \
          --prefix PATH : "$out/libexec/xscreensaver" \
          --prefix PATH : "${lib.makeBinPath [ coreutils perl ]}" \
          --prefix PERL5LIB ':' $PERL5LIB
      done
    '' + lib.optionalString forceInstallAllHacks ''
      make -j$NIX_BUILD_CORES -C hacks/glx dnalogo
  