add a newsyslog.conf that matches the all.debug.

Set NOxxx= before <bsd.own.mk> is pulled in (even indirectly).
Otherwise the appropriate MKxxx=no won't be defined .

MKfoo=no -> NOfoo

example syslogd(8) config files (to be installed as /etc/syslog.conf):
all.debug - each facility gets logged to its own file