Fix missing symbols in i810 driver
 Fix xdm on Alpha by using NetBSD's version of Wraphelp.c
 Report buttons 7 and when using sysmouse protocol
 Fix missing symbols in r128 driver.
 Reset /usr/X11R6/bin/X to Xwrapper-4 after install if Xwrapper-4 exists.
PR:  i386/44203