https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116657
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I've inspected the tzdata.zi file in the Arch tzdata-2024b-1-x86_64.pkg.tar.zst
package and the problem is the use of %z in the FORMAT field, as described in
the r15-1663-g0ca8d56f208571 commit:
The vanguard format makes use of %z in Zone FORMAT fields, which caused
an exception to be thrown from ZoneInfo::set_abbrev because no % or /
characters were expected when a Zone doesn't use a named Rule. The
ZoneInfo::to(sys_info&) function now uses format_abbrev_str to replace
any %z with the current offset. Although format_abbrev_str also checks
for %s and STD/DST formats, those only make sense when a named Rule is
in effect, so won't occur when ZoneInfo::to(sys_info&) is used.
So as I suspected, this is due to enabling (some, or all) vanguard features in
the latest Arch package, NOT caused by anything in the 2024b update directly.
It seems to be a change in how Arch builds the package.
