[Bug libstdc++/51653] More compact std::tuple

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51653

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #7)
> We should do it for the --enable-symvers=gnu-versioned-namespace build.

s/should/could/

If it makes the implementation diverge too much (and requires support
elsewhere, like std::get and std::tuple_element) maybe it's not worth it. But I
don't think we've concluded it's WONTFIX yet.