[Bug libstdc++/69945] Provide an equivalent of __libc_freeres to release emergency EH pool memory

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69945

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
but as the allocator lives in libsupc++ which is static only we can add that
symbol there (unversioned)?