[Xcb] update to libxcb 1.12 breaks 32bit applications

[Ran Benita]

On Thu, Jun 09, 2016 at 01:46:56PM +0200, G. Schlisio wrote:
> >> It looks like it spawns subprocesses (some startup script maybe). Please
> >> try `valgrind --trace-children ./my_program` then.
> > 
> > Meant to write `--trace-children=yes`.
> 
> ok, with valgrind-multilib and tracing children i yield this:
> http://pastebin.com/nhyJ4hY3
> 
> crashes but at first glance i dont see something like a chrash report.

There are some errors, but seem unrelated. So, this didn't help.

If you are willing to put in a bit of effort, given that the program
works with 1.11 but not with 1.12, the best way would be to find the git
commit which caused the regression. The easiest way to do that is to use
"git bisect".

You would do this like so (from your libxcb git clone):

    git checkout master
    git bisect start
    git bisect bad
    git bisect good 1.11

Now, it will switch to some commit; you then need to recompile and test
if the problem is there or not. If it still crashes, write

    git bisect bad

if it doesn't, write

    git bisect good

You should repeat this (about 6 times) until git hones down on the first
bad commit (you can also automate the testing step with `git bisect
run`, see `man git bisect`).