anchor.diff:      expat
     ];
   
  -  buildInputs = lib.optionals x11Support [
  -    libX11
  -    libICE
  -    libSM
  -  ] ++ lib.optional stdenv.isLinux systemd;
  +  buildInputs =
  +    lib.optionals x11Support [
  +      libX11
  +      libICE
  +      libSM
  +    ] ++ lib.optional enableSystemd systemd;
     # ToDo: optional selinux?
   
     configureFlags = [
  
positive.code: , fetchurl
  , pkgconfig
  , expat
  , systemd
  , libX11 ? null
  , libICE ? null
  
negative.code: assert
    x11Support ->
      libX11 != null && libICE != null && libSM != null;
  
  assert enableSystemd -> systemd != null;
  
  stdenv.mkDerivation rec {
    pname = "dbus";
  