[Bug libstdc++/108211] New: std::chrono::current_zone() fails if zone only has one component

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108211

            Bug ID: 108211
           Summary: std::chrono::current_zone() fails if zone only has one
                    component
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

$ ls -l /etc/localtime
lrwxrwxrwx. 1 root root 25 Mar 15  2017 /etc/localtime ->
../usr/share/zoneinfo/UTC


Libstdc++ incorrectly assumes the local timezone will be "foo/bar" and so it
breaks for "UTC" or any other name without a slash in it.

terminate called after throwing an instance of 'std::runtime_error'
  what():  tzdb: cannot determine current zone


This causes:

FAIL: std/time/tzdb/1.cc execution test
FAIL: std/time/zoned_time/custom.cc execution test