[Bug bootstrap/52509] target libstdc++-v3 should not be bootstrapped, libstdc++-v3 should also be a host_module (bootstrapped)

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52509

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
No objections from me. I'm not sure how representative of real C++ code the
bits in libstdc++.so are anyway.