c5666305@hkstar.com said:
> I encountered an error when I tried to make a new kernel with source
> upto dec 15, 1999.  The error was reported by cc1 which pointed to the
> vga.c:249: incompatible pointer type error.

The only reason I can imagine is that you picked up an inconsistent tree.
Do you have the matching
dev/ic/vga.c 1.22 (or later)
and
dev/wscons/wsdisplayvar.h 1.14?

best regards
Matthias