anchor.diff: -{ stdenv, fetchurl, autoreconfHook, pkgconfig, perl, python, libxml2Python, libxslt, which
  +{ stdenv, fetchurl, autoreconfHook, pkgconfig, perl, python3, libxml2Python, libxslt, which
   , docbook_xml_dtd_43, docbook_xsl, gnome-doc-utils, gettext, itstool
   , withDblatex ? false, dblatex
   }:
   
   stdenv.mkDerivation rec {
     name = "gtk-doc-${version}";
  -  version = "1.28";
  +  version = "1.29";
   
     src = fetchurl {
       url = "mirror://gnome/sources/gtk-doc/${version}/${name}.tar.xz";
  -    sha256 = "05apmwibkmn1icx05l8aw241lhymcx01zvk5i499cb150bijj7li";
  +    sha256 = "1cc6yl8l275qn3zpjl6f0s4fwmkczngjr9hhsdv74mln4h08wmql";
     };
   
     patches = [
  
positive.code:   # Make six available for binaries, python.withPackages creates a wrapper
    # but scripts are not allowed in shebangs so we link it into sys.path.
    postInstall = ''
      ln -s ${python.pkgs.six}/${python.sitePackages}/* $out/share/gtk-doc/python/
    '';
  
    doCheck = false; # requires a lot of stuff
  
negative.code: 
    nativeBuildInputs = [ autoreconfHook ];
    buildInputs =
      [ pkgconfig perl python3 libxml2Python libxslt docbook_xml_dtd_43 docbook_xsl
        gnome-doc-utils gettext which itstool
      ] ++ stdenv.lib.optional withDblatex dblatex;
  
  