[Xcb] Patches to make xpyb compile with xcb-proto 1.8

[Arnaud Fontaine]

Hello,

xpyb fails to build  with xcb-proto 1.8, so here are some  patches I tested by
checking the differences between the output with xcbgen 1.7 (without my patch)
and  xcbgen 1.8  (with these  patches).   However, I'm  not sure  if they  are
completely right as  I don't know much about xpyb.  Could someone review them?
Many thanks.

Regards,
Arnaud Fontaine