I needed stunnel to log to the MAIL facility in order to get
stunnel-wrapped imap to work correctly with my homegrown
imap-before-SMTP antirelay solution for sendmail 8. For a few
iterations, I just rebuilt stunnel with a modified log.c for each
install, but it has occurred to me that for similar reasons others
might want to change the syslog facility to which stunnel writes.
Inspired vaguely by sshd's SyslogFacility configuration parameter,
I've hacked in some code to allow runtime specification of log
facilities.

This patch now works natively with the '-D' option to provide
both log level and facility for sysloging, ala  '-D news.5'