[Xcb] Bug 6254: remove XCB's xproto/X11 dependency

[Jeremy Kolb]

> The <enum> construct generates very wordy symbols. (Example: enum  {
> XCBWindowClassInputOutput = 1 } XCBWindowClass; where previously  one
> only had to deal with InputOutput). You could argue that this is  a
> feature, though perhaps not for masks. Maybe an option to prefix  the
> members just with "XCB" and not the full name of the enumeration?
> 

I really think we need a better way of handling enums.  The names are
way too unwieldly.  Vincent and I have talked about this but we couldn't
come up with a good solution.  I really think it needs to be changed
though, not developer friendly at all.

Jeremy