[Bug libstdc++/60662] simple use of call_once throws a system_error exception, but not if sleep_for is called beforehand

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60662

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Probably related to PR 55394