[Xcb] libxcb/libX11 deadlocking and asserting in multi-threaded use

[Nicholas Allen]

Hi,

I've tried wrapping all calls into XLockDisplay but this made no
difference. Also according to the documentation I found on the internet
this is only needed to group multiple requests into one composite change
and the library should be thread safe without needing to call them (in
which case each xlib call is a composite change). The only requirement
was that XInitThreads is called. Perhaps this documentation was invalid
or out of date? I can't remember the link where I read it.

In the real Java implementation though we are calling
XLockDisplay/XUnlockDisplay from each thread.

Nick