[Bug libstdc++/99181] char_traits<char> (and thus string_view) compares strings differently in constexpr and non-constexpr contexts

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99181

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #5)
> Fixed on the trunk, probably needs backporting to 10/9/8 branches.

Yes, all three branches. It's been wrong since r249137 on trunk, which I
backported to gcc-7 (for 7.3.0) as r252030