Reported by Vekhir - the match-date test failed some time around the DST changeover this year,
specifically the "in the last 45 seconds" bit of the test.

The code in Darcs.Util.DateMatcher does do some fast-and-loose stuff with times
(particularly the way the MCalendarTime structure works).

[03:34] <Vekhir> So, I've setup a VM where I control the time and did some testing:
[03:34] <Vekhir> 1. The issue is reproducible
[03:34] <Vekhir> 2. The issue occurs between 04:00:27 CEST and 05:00:28 CEST (Berlin, Germany)
[03:34] <Vekhir> 3. The issue does not occur with 03:59:46 CEST and 05:01:29 CEST
[03:34] <Vekhir> 4. The issue occurs with 06:00:36 EEST (Helsinki, Finland; one hour ahead of CEST)
[03:34] <Vekhir> 5. The issue does not occur with 03:31:45 WEST (Lisbon, Portugal; one hour behind CEST)
[03:34] <Vekhir> Interesting is the success with WEST where I would expect failure. Notably, WET (non-DST in 
Lisbon) is equivalent to UTC.
[03:34] <Vekhir> All times are, naturally, on 31.03.2024. The jump to DST is at 1:00 UTC == 2:00 WEST == 3:00 
CEST == 4:00 EEST
[03:34] <Vekhir> Hopefully this information will prove useful in the future.