dead kernel debugging. The previous code was a "do nothing".
The most obvious side effect of this is that you can now do things like
this and reasonably expect them to work:
dmesg -M /var/crash/vmcore.3 -N /var/crash/kernel.3
ps -axl -M /var/crash/vmcore.3 -N /var/crash/kernel.3
A good deal of this was lifted from the gdb code to do this, as well as
from NetBSD's libkvm (which has completely different VM macros)