bug#7905: 24.0.50; VC not updating file status properly anymore after commit from vc-dir

[Tim Van Holder <tim.vanholder@gmail.com>]

On 31 January 2011 15:10, Andreas Schwab <schwab@linux-m68k.org> wrote:
> Tim Van Holder <tim.vanholder@gmail.com> writes:
>
>> Checking the behaviour of (encode-time) I see that
>>   (encode-time 16 18 15 11 1 2011 2 nil 3600)
>>   (encode-time 16 18 15 11 1 2011 2 nil 0)
>> both return the same value "(19756 26280)"
>
> You should find out why.
>
> Andreas.

I tried treating a zone of 0 the same way as a nil zone (i.e. set TZ
to UTZ0), in case it was the XXX-0:00:00 TZ setting that was not
working:

      if (EQ (zone, Qt) || (INTEGERP (zone) && XINT (zone) == 0))
	tzstring = "UTC0";

but that made no difference: encode-time completely ignores the zone
setting (whether nil, t, 0, 3600, 17, 36000, "CET", "UTC", "FOO").

In order to do the (apparent) right thing, encode-time seems to rely
on mktime() to take $TZ into account (otherwise there is no point in
saving/restoring the environment with a specific TZ value).
However, lib/mktime.c (which is in use by my emacs build) does not
seem to refer to any timezone info at all - neither $TZ nor tm_zone is
referenced; it seems to rely on localtime() to deal with that. I guess
that's not the case for my localtime() (from glibc 2.3.6).