Log Message:
Update libart2 to 2.3.11. Changes since 2.3.10:

* art_render_svp.c (art_render_svp_callback,
  art_render_svp_callback_span, art_render_svp_callback_opacity,
  art_render_svp_callback_opacity_span): if no runs would
  normally be emitted, but start is greater than zero, emit a
  single run covering the entire width of the rendered region.
* autogen.sh: hardcode aclocal-1.4/automake-1.4 so that users with
  both automake 1.6 and 1.4 installed get the right automake. Means
  compilation from CVS will now require the latest automake 1.4
  release, or manually creating symlinks called "automake-1.4" and
  "aclocal-1.4".