connection issue using xcb in libX11

[Jeremy Huddleston]

It seems that using xtrans in libX11 results in connection fallbacks that don't exist in xcb.  If I use xscope (built with --disable-xtrans):

Terminal 1> xscope -i5 -o0
Terminal 2> ls -l /tmp/.X11-unix
total 0
srwxrwxrwx 1 jeremy wheel 0 Apr 27 02:25 X0

I am able to connect through xscope using:
Terminal 2> DISPLAY=:5 /opt/X11_xtrans/bin/xterm

where /opt/X11_xtrans/bin/xterm uses an xtrans based libX11.

I am not able to connect through xscope using:
Terminal 2> DISPLAY=:5 /opt/X11_xcb/bin/xterm

where /opt/X11_xcb/bin/xterm uses an xcb based libX11.

I am able to connect if I instead use TCP with:
Terminal 2> DISPLAY=localhost:5 /opt/X11_xcb/bin/xterm

So xtrans seems to fallback on TCP when it does not find an appropriate unix socket, but xcb does not have this fallback.

Is this fallback something that should be added to xcb itself, or is this something that should be addressed in libX11?