anchor.diff:        # 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.
  
positive.code: , libusb ? null, gnutls ? null, avahi ? null, libpaper ? null
  }:
  
  let version = "2.1.2"; in
  
  with stdenv.lib;
  stdenv.mkDerivation {
  
negative.code: 
    src = fetchurl {
      url = "https://www.cups.org/software/${version}/cups-${version}-source.tar.bz2";
      sha256 = "1gaakz24k6x5nc09rmpiq0xq20j1qdjc3szag8qwmyi4ky6ydmg1";
    };
  
    buildInputs = [ pkgconfig zlib libjpeg libpng libtiff libusb gnutls libpaper ]
  