[cairo] Multithreaded cairo-perf

[Chris Wilson]

This branch and it compatriots are now online and browsable at
http://gitweb.freedesktop.org/?p=users/ickle/cairo;a=shortlog;h=threaded-testcases
A big thank you to Carl Worth for setting this up.

Similary, I'm pushing the valgrind skins that I've been developing
whilst testing Cairo to
http://gitweb.freedesktop.org/?p=users/ickle/valgrind;a=summary

And now it's time for a break before reviewing the
attribute(warn_unused_result) branch again.
--
Chris Wilson