anchor.diff:    configureFlags = [
       "--enable-glibtest"
       "--enable-Bsymbolic"
  -    "--enable-x11-backend"
  +    (enFlag "x11-backend" (xorg != null) null)
       "--disable-win32-backend"
       "--disable-quartz-backend"
  -    "--enable-wayland-backend"
  +    "--enable-gdk-backend"
  +    (enFlag "wayland-backend" (wayland != null) null)
       "--enable-egl-backend"
       "--disable-mir-backend"
       "--disable-cex100-backend"
  -    "--enable-wayland-compositor"
  -    "--enable-tslib-input"
  +    # TODO: tslib, touch screen support
  +    "--disable-tslib-input"
       "--enable-evdev-input"
  -    "--enable-xinput"
  -    "--enable-gdk-pixbuf"
  +    (enFlag "wayland-compositor" (wayland != null) null)
  +    (enFlag "xinput" (xorg != null) null)
  +    (enFlag "gdk-pixbuf" (gdk-pixbuf != null) null)
       "--disable-debug"
  -    (enFlag "introspection" (gobject-introspection != null) null)
       "--disable-deprecated"
       "--disable-maintainer-flags"
  +    #"--disable-Werror"
       "--disable-gcov"
  -    "--enable-introspection"
  +    (enFlag "introspection" (gobject-introspection != null) null)
       "--disable-gtk-doc"
       "--disable-gtk-doc-html"
       "--disable-gtk-doc-pdf"
  
positive.code:     "--disable-installed-tests"
      "--disable-always-build-tests"
      "--disable-examples"
      "--with-x"
    ];
  
    meta = with stdenv.lib; {
  
negative.code: 
  with {
    inherit (stdenv.lib)
      enFlag
      optionals
      wtFlag;
  };
  
  assert xorg != null ->
    xorg.inputproto != null
    && xorg.libX11 != null
    && xorg.libXcomposite != null
    && xorg.libXdamage != null
    && xorg.libXext != null
    && xorg.libXi != null
    && xorg.libXrandr != null;
  
  stdenv.mkDerivation rec {
    name = "clutter-${version}";
    versionMajor = "1.26";
    versionMinor = "0";
    version = "${versionMajor}.${versionMinor}";
  
    src = fetchurl {
      url = "mirror://gnome/sources/clutter/${versionMajor}/${name}.tar.xz";
      sha256 = "67514e7824b3feb4723164084b36d6ce1ae41cb3a9897e9f1a56c8334993ce06";
    };
  
    nativeBuildInputs = [
  