[Bug lto/89358] [7/8/9 Regression] Combining -std=c++14 and -std=c++17 objects gives ODR warnings

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89358

--- Comment #15 from Jonathan Wakely <redi at gcc dot gnu.org> ---
and s/itroduces/introduces/