anchor.diff:    libarchive = buildPythonPackage rec {
       version = "3.1.2-1";
       name = "libarchive-${version}";
  +    disabled = isPy3k;
   
       src = fetchurl {
         url = "http://python-libarchive.googlecode.com/files/python-libarchive-${version}.tar.gz";
  
positive.code: 
    pygtk = import ../development/python-modules/pygtk {
      inherit (pkgs) fetchurl stdenv pkgconfig gtk;
      inherit python buildPythonPackage pygobject pycairo;
    };
  
    # XXX: how can we get an override here?
    #pyGtkGlade = pygtk.override {
  
negative.code:   pyGtkGlade = import ../development/python-modules/pygtk {
      inherit (pkgs) fetchurl stdenv pkgconfig gtk;
      inherit (pkgs.gnome) libglade;
      inherit python buildPythonPackage pygobject pycairo isPy3k;
    };
  
    pyqt4 = import ../development/python-modules/pyqt/4.x.nix {
  