[Xcb] connection issue using xcb in libX11

[Alan Coopersmith]

Josh Triplett wrote:
> I find it quite dubious that real applications expect DISPLAY=:0 to
> connect to TCP.  It certainly violates the principle of least surprise.

But it's what the Xlib standard spec has always required.  When no hostname
or transport protocol is provided, Xlib is supposed to pick the "best"
transport available.  If TCP to localhost is the only one accepting
connections, it would be the best.

xcb is of course free to implement a different spec at its level, but
Xlib should continue to honor this when applications call XOpenDisplay()
regardless of whether Xlib calls xtrans or libxcb to make the connection.

-- 
	-Alan Coopersmith-        alan.coopersmith at oracle.com
	 Oracle Solaris Platform Engineering: X Window System