I wrote:
>I booted a 1.2D kernel yesterday and started a make build,
>The make build ran fine up until it was building gnu/libexec/uucp 
>where make died with a segmentation violation.

To cut a long story short, since I was looking at having to restore
from a tape anyway, I tried ldconfig, and re-ran make in 
gnu/libexec/uucp.  The system ran for  a few seconds and jammed tight.
Unfortunately my 9 year old had already hosed the console the day before
(an X session with no I/O working, I don't know how, but these kids manage 
to screw the machine more in one weekend than I do in a year, most common
problem is /dev/ttyv0 just stops responding to the keyboard...)

So, I had no choice but to hit the reset button.  System came up ok
and cd /usr/src/gnu/libexec/uucp && make worked fine
as did cd /usr/src/sys && make, so what the ^*S! I did a make install.
That ran fine and I rebooted.  

So far the machine is running ok and there were no core files from cron jobs
last night.

--sjg