[Bug libstdc++/125450] [16/17 Regression] std::optional breaks in C++26 freestanding mode

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125450

--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This is now https://cplusplus.github.io/LWG/issue4586