tzcode: garbage collect references to tzsetwall

[val_packett.cool]

Summary

It was removed with the recent update to upstream tzcode, but references in the header, symbol map and man pages remained.

Fixes: bc42155199 ("Bring our tzcode up to date.")
Reported by: ld.lld 16 being --no-undefined-version by default
Sponsored by: https://www.patreon.com/valpackett

[des]

I honestly hadn't noticed that the tzcode update removed tzsetwall(3).

On the one hand, it's useless and nobody should be calling it.

On the other hand, we've had it for 30+ years and it's arguably part of our ABI.

On the gripping hand, this was merged to stable/13 eight days ago and nobody (including the package builders) noticed.

What do you think @emaste @imp? Should we reintroduce it as an alias for tzset(3), or implement something ourselves? I think the closest thing to the original spirit is “like tzset(3) but ignores the TZ environment variable, taking only /etc/localtime into account.”

[des]

@val_packett.cool can you file a PR instead and abandon this review?

[emaste]

Discussed briefly on IRC - suggestion was to make tzsetwall an alias for tzset, with linker magic to emit a deprecation warning

[des]

See D38445.

[val_packett.cool]

sure, D38445 LGTM