[Bug libstdc++/78420] [6/7/8 Regression] std::less is not a total order with -O2 enabled

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78420

--- Comment #31 from Jonathan Wakely <redi at gcc dot gnu.org> ---
First let me try the metaprogramming way to detect when we convert to pointers,
and see if it can be done just in the library. I'm working on that ...