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