[Bug libgcc/71744] Concurrently throwing exceptions is not scalable

[gleb at scylladb dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71744

--- Comment #13 from Gleb Natapov <gleb at scylladb dot com> ---
I've done it with my version of it which does basically the same. The patch by
itself has no effect on scalability, but in conjunction with this fix for glibc
https://patchwork.ozlabs.org/patch/652301/ I get very good results.