Sync newsyslog(8) with FreeBSD's current code.
New things:
* Re-ordering of the rotate/signal steps. First, rotate all files which
need to be rotated and then send a single signal to each daemon that
needs to be notified. This way, each daemon will only be signaled once
instead of once per file.
* Allow /var/log to be a symbolic link.
* -d option for specifying an alternate root for log files.
* -D option for debugging purposes.
* -N option to suppress log file rotation (intended to be used in
conjunction with -C and -CC).
* Bug fixes and minor improvements.
Note: FreeBSD's r1.107 of newsyslog.c was not brought in as it generates
a warning in DragonFly instead of fixing one.