[swbz 29035] mktime vs non-DST

[DJ Delorie]

Paul Eggert <eggert@cs.ucla.edu> writes:
> Although I'm not seeing how BZ#29035 led to your diagnosis

We had a customer bz with a similar problem.  I wrote a script to test
every transition in every zoneinfo file, plus a january/june check, for
every tm_isdst.  The patterns tend to jump out at you after that.

> This is a bit fancier than what you suggested, but I expect it'll fix
> BZ#29035 while it's also fixing the bug reported against Gnulib.

It does stop mktime from returning -1 in the problem case, but it still
returns a different value than pre-2.29.  Older code returned the
standard time result, your patches return a DST result, even if the zone
has no DST.  I think this makes it more consistent, but I don't know
what the consequences of "different than before" will be here.