tzsetup: make UTC the first (default) region

[brooks]

Summary

Many system admins prefer to configure their systems to UTC and it's a
reasonable default when installing, making it easier to get a usable
system by just hitting <return> repeatidly.

Renumber UTC to 0 to preserve the finger memory of those selecting a
region by shortcut.

[jrtc27]

usr.sbin/tzsetup/tzsetup.c

208

This is based off index in the array (yes, ew), so needs updating

[brooks]

Update ocean indices

[jrtc27]

The goal makes sense to me and I think this is now correct (maybe worth verifying you do see the right messages when selecting oceans vs continents?)

[brooks]

In D42383#967126, @jrtc27 wrote:

The goal makes sense to me and I think this is now correct (maybe worth verifying you do see the right messages when selecting oceans vs continents?)

Hand checked and right headers are used. (Antarctica's message is a bit silly since Antarctica is one of the two choices and isn't a country, but that's something for another commit.)

[emaste]

usr.sbin/tzsetup/tzsetup.c

208

sigh, I'm not sure OCEANP makes anything clearer :)

[brooks]

usr.sbin/tzsetup/tzsetup.c

208

I'm slightly tempted to gratuitously define an enum or set of defines and then use designed initializers. Something like:

enum continents {
 c_UTC,
 ...
};

continent_names[] = {
 [c_UTC] = { "UTC",	&utc },
 ...
};
...

but probably not tempted enough to bother...

[jrtc27]

usr.sbin/tzsetup/tzsetup.c

208

I have thoughts for how to clean it up, but wasn't going to play around with it until after you'd committed this

[emaste]

usr.sbin/tzsetup/tzsetup.c

208

Yeah, I'd say get this review in and we can see about incremental improvement from there