[Xcb] xcb recursive write not protected in all cases?

[Josh Triplett]

On Thu, Dec 26, 2013 at 01:25:50PM -0800, Keith Packard wrote:
> Uli Schlachter <psychon at znc.in> writes:
> > After having figured all of this out today, who wants to write this down? And
> > where? Some Wiki page called "ThreadSafetyInternals"?
> 
> Sounds like we've got a good start here...

I'd actually suggest putting it in the XCB source code, under the doc/
directory.  Easier to keep it in sync with the code that way, and easier
to find it when trying to figure out how the code works.  (Not least of
which because, through naming some of the functions and variables and
locks in question, it'll show up in the obvious greps.)

- Josh Triplett