additional actions before printing it.  OK rzalamena@

OK bcook@ jung@

and actually not a "logging" function.  No functional change.

I mirrored from smtpd a little too literally.

Reduces the number of log.c snowflakes by a little, and gives ntpd a
variadic fatal() function to be used later.
ok deraadt@

format string, create a temporary message.
OK claudio@

priority.
ok gwk, mbalmer, weingart
"explicit non-ok from" henning

before, it would log with LOG_DEBUG to syslog when !debug

it is just capable of answering (s)ntp4 requests with the local time
for now.
imsg/buffer and logging framework from bgpd, ntp protocol hackery
with Alexander Guy