[Bug libstdc++/57272] node-based containers don't use allocator's pointer type internally

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57272

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
c.f. http://cplusplus.github.io/LWG/lwg-active.html#2261