Let's allow distros to change the support URL to expose in catalog entries by
default. It doesn't make sense to direct end-users to the upstream project for
common errors.
This adds a --with-support-url= switch to configure, which allows overriding
the default at build-time.
Fixes: #2516
We generally follow the rule that for time settings we suffix the setting name
with "Sec" to indicate the default unit if none is specified. The only
exception was the rate limiting interval settings. Fix this, and keep the old
names for compatibility.
Do the same for journald's RateLimitInterval= setting
Lennart Poettering