journald-source: New source module is implemented

The module does not require installed systemd-journal development package
Unit tests also implemented and these tests can run on non-journald systems

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>
geoip: Fix local state initialisation

When running with threaded(yes), local state was never initialised,
because we did that at module load time, which happens in a different
thread. Instead, we now initialise the local state on each function
call, unless already initialised.

This fixes #228.

Reported-by: Fabien Wernli
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
afsocket: syslog-ng receives credentials via UDS only on FreeBSD and on Linux

Signed-off-by: Budai Laszlo <Laszlo.Budai@balabit.com>
Merge pull request #231 from lbudai/f/credential_pass

afsocket: syslog-ng receives credentials via UDS only on FreeBSD and on ...
Merge pull request #230 from algernon/h/3.6/geoip/threaded-fix

geoip: Fix local state initialisation
systemd-journal: make it possible to turn on/off systemd-journal usage

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>
Merge pull request #229 from juhaszviktor/3.6/f/journald-source

journald-source: New source module is implemented
systemd-journald: remove reference to non-existing header file

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>
Merge pull request #232 from juhaszviktor/3.6/f/journald-source

systemd-journald: remove reference to non-existing header file
systemd-journal: make log_fetch_limit option available via config file

Signed-off-by: Juhász Viktor <viktor.juhasz@balabit.com>
Merge pull request #233 from juhaszviktor/3.6/f/journald-source

systemd-journal: make log_fetch_limit option available via config file
Fix a few compiler warnings

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Merge pull request #234 from algernon/h/3.6/warning-fixes

Fix a few compiler warnings
service-management: use virtual functions
systemd-syslog: refactoring WIP