[Bug libstdc++/84766] __verbose_terminate_handler mistakes parallel unhandled exceptions for recursive std::terminate() calls

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84766

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I don't think we want to use another TLS entry just for this handler, so I'm
leaning towards the nice suggestion to say "reentrant" instead.