Import WIP Xorg-Server-1.20'fied monolithic Xsun servers.

This is based on 1.10 version imported into xorg-server.old and
all upstream API changes between xorg-server 1.10 and 1.20 are
applied almost mechanically.
https://github.com/tsutsui/xorg-server-Xsun/commits/xorg-server-1.20

Xsun and XsunMono servers are also confirmed working with bwtwo on
3/60 and tme, and cgtwo on tme. XKB stuff is still to be resolved.