[Bug libstdc++/64967] [5 Regression] Bootstrap fails due to errors in libstdc++ sources with `--enable-symvers=gnu-versioned-namespace'

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64967

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Or drop the gnu-versioned-namespace support altogether.
Anyway, if you don't, bumping it to _8 and always using the new ABI sounds like
a good plan to me.