[Bug c++/104514] add feature to create a pointer to a fixed address as constexpr

[q.gcc--- via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104514

--- Comment #5 from steveren <q....@rsn-tech.co.uk> ---
In fairness, I was asking for a lost capability to be restored, and I think it
was implicit that a proper mechanism would be better than the pre-existing
kluge :-)