anchor.diff:  { fetchurl, fetchpatch, substituteAll, stdenv, meson, ninja, pkgconfig, gnome3, json-glib, libcroco, gettext, libsecret
  -, python3Packages, libsoup, polkit, clutter, networkmanager, docbook_xsl , docbook_xsl_ns, at-spi2-core
  +, python3, libsoup, polkit, clutter, networkmanager, docbook_xsl , docbook_xsl_ns, at-spi2-core
   , libstartup_notification, telepathy-glib, telepathy-logger, libXtst, unzip, glibcLocales, shared-mime-info
   , libgweather, libcanberra-gtk3, librsvg, geoclue2, perl, docbook_xml_dtd_42, desktop-file-utils
   , libpulseaudio, libical, gobject-introspection, gstreamer, wrapGAppsHook, libxslt, gcr, caribou
  
positive.code: # http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/gnome-base/gnome-shell/gnome-shell-3.10.2.1.ebuild?revision=1.3&view=markup
  
  let
    pythonEnv = python3Packages.python.withPackages ( ps: with ps; [ pygobject3 ] );
  
  in stdenv.mkDerivation rec {
    name = "gnome-shell-${version}";
  
negative.code: 
    nativeBuildInputs = [
      meson ninja pkgconfig gettext docbook_xsl docbook_xsl_ns docbook_xml_dtd_42 perl wrapGAppsHook glibcLocales
      sassc desktop-file-utils libxslt.bin python3
    ];
    buildInputs = [
      systemd caribou
  