Update to 8.34.0

Add patches to configuration system to allow specifying whether
syslog(3) generates RFC5424 format messages, instead of RFC3164.

Set RFC5424 as the syslog(3) default for OSVER >= 1200061. See:
https://reviews.freebsd.org/D14951 This is primarily a convenience so
that users of rsyslog8 will not have to modify their rsyslog.conf when
upgrading to a version of FreeBSD that generates RFC5424 from
syslog(3). I will submit these patches upstream in due course.