This still doesn't actually really _use_ it properly, nor make any
distinction between different DST rules, but at least we could (if
we wanted to) fake it a bit better.
Right now the code actually still says "it's always summer". I'm
from Finland, I don't like winter.
...since everything out there is either strange (libc mktime has issues
with timezones) or introduces unnecessary dependencies for people (libcurl).
This goes back to the old date parsing, but moves it out into a file of
its own, and does the "struct tm" to "seconds since epoch" handling by
hand.
I grepped through the tz-database and it seems there's one "country"
left that has non-60-minute DST: Lord Howe Island. All others dropped
that before 1970.
