Logging in systemd environment

[Torsten Hilbrich]

Am 17.05.2017 um 15:33 schrieb Aleksander Morgado:
> Ideally, the systemd journal support should be automatically enabled
> during the build if systemd is found (e.g. as we do with
> --with-suspend-resume). It should be possible to explicitly disable it
> as well. This could be --with-systemd-journal=[yes|no|auto].
> 
> And then, the ModemManager program should have a specific option to
> dump logs via the systemd journal, e.g. --log-journal.  Something like
> that.
> 
> What do you think?

This sounds fine, I will start working on some patches. I already saw
your other changes regarding refactoring the logging options and will
base my work on those commits.

	Torsten