statistics from -z are now a bit different due to changes in the
way statistics are now measured. Reproduce with some amount of
accuracy the slightly obscure layouts adopted by the two kernel
sysctls. In the future, we might want to normalize them.
GC dosysctl(), which is now no longer used.
MFC after: 1 week
The use of libkvm for post-mortem analysis is still supported (though it
could use more testing). We can now remove vmstat's setgid bit.
While I'm here, hack the interrupt listing code to not display interrupts
that haven't occurred unless the -a option was given on the command line,
and document this change.
