Seems journal logging fails on NetBSD (no surprise), but has some
unwanted/not-fully-understood side-effects.
In any case, outside Linux there's no use in even trying to use
journald; so we don't do that anymore.
Add conditional support for syslog (requires glib 2.80).
Update all cc code using .clang-format; please do so as well for future PRs
etc.; emacs has a handy 'clang-format' mode to make this automatic.
For comparing old changes with git blame, we can disregard this one using
--ignore-rev
(see https://www.moxio.com/blog/43/ignoring-bulk-change-commits-with-git-blame )
Some #includes were missing for the latter (but only noticeable on some
systems - e.g., build breaks on Cygwin).
So let's replace with something that works equally everywhere.
Fixes: #2060
