[Xcb] [PATCH Xlib 1/3] Hoist most of _XConnectXCB into XOpenDisplay, and simplify

[josh at joshtriplett.org]

On Wed, Jun 17, 2015 at 01:09:00PM -0700, Jasper St. Pierre wrote:
> Why not use -displayfd to get the display number to connect to? This
> patch is still a good idea, I think, but it's not required.

This is useful for any API that wants to interoperate between XCB and
Xlib without specifically receiving an Xlib Display.  It means APIs can
convert over to XCB without requiring that all their dependencies do so
first.

- Josh Triplett