anchor.diff:        # Work around a Makefile bug.
         "CUPS_PRIMARY_SYSTEM_GROUP=root"
       ];
  +
  +  enableParallelBuilding = true;
   
     postInstall = ''
         # Delete obsolete stuff that conflicts with cups-filters.
  
positive.code:       # Idem for /etc.
        "PAMDIR=$(out)/etc/pam.d"
        "DBUSDIR=$(out)/etc/dbus-1"
        "INITDIR=$(out)/etc/rc.d"
        "XINETD=$(out)/etc/xinetd.d"
        "SERVERROOT=$(out)/etc/cups"
        # Idem for /usr.
  
negative.code: 
  ### IMPORTANT: before updating cups, make sure the nixos/tests/printing.nix test
  ### works at least for your platform.
  let version = "2.1.3"; in
  
  with stdenv.lib;
  stdenv.mkDerivation {
  