[Xcb] what needs to happen for libxcb 1.8?

[Jamey Sharp]

A number of important bug fixes have piled up on libxcb master, so we
probably need a new release soon. But I'm not sure what we have now is
suitable for release. So, questions for all of you:

- What issues are you aware of?
- Are there bugs filed in Bugzilla for them?
- Has somebody suggested patches or sensible plans for fixes?

For my part: I seem to recall somebody saying that ListExtensions is
broken in master. That seems important. :-) Reviewing the commits
since 1.7, it looks to me like the XKB merge was the only big,
high-risk change, so I assume that's related. I guess Evgeny's
alignment proposal is intended as a fix? Since it would be great to
have XKB support, I'd like to see this cleaned up soon; the
alternative is to revert the XKB merge, do a release, and then try
getting XKB in again.

On the other side, we have some good stuff: Win32 support, fixes for
the X Test Suite, fixes for memory leaks, better documentation, and
new API.

Jamey