Parsing failure for date time with timezone name

[jfinkels]

parse_datetime fails to parse "1997-01-01 00:00:00 UTC"

[drinkcat]

I think fixing this properly (and easily) will require switching to jiff, partly because, with chrono, it's very tricky to include (or not) a full timezone database depending on the OS (see #7849 for some of the struggle).

[bdrung]

I ran into this bug when installing tzdata using rust-coreutils on Ubuntu. The tzdata postinst uses following code:

 UTdate=$(LC_ALL=C TZ=UTC0 date)
 TZdate=$(unset TZ ; LANG=C date -d "$UTdate")

That works with coreutils, but fails with rust-coreutils:

$ LANG=C coreutils date -d "Tue May 13 11:50:05 UTC 2025"
date: invalid date 'Tue May 13 11:50:05 UTC 2025'

Ubuntu-Bug: https://bugs.launchpad.net/ubuntu/+source/tzdata/+bug/2110537