[Bug libstdc++/121174] std::dextents was not found, which prevented std::mdspan from specifying dimensions at runtime

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121174

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Most likely this feature of c++26 has not been implemented yet ...