[Bug libstdc++/70607] The return type of std::conj must be std::complex<T>

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70607

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think Marc's point is that GCC is doing what DR 1137 says ... but it looks as
though the DR resolution never made it into C++11.