[tz] Irish Standard Time vs Irish Summer Time

[Zefram]

Michael Deckers via tz wrote:
>  I'm a bit surprised that it seems to be so easy to extend the
>  input format for zic (negative SAVE values)

That's not a change to the format that zic accepts.  Note the lack of
zic.c patch.

>                         unless we want to allow for negative
>  AT values as well.

zic already does allow negative AT times.  There are no examples in the
database, though.

zic.8 ought to be patched to make explicit that AT and SAVE have no
small range limits.

-zefram