[Bug libstdc++/85998] feature request: support C++17 parallel STL

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85998

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
https://gcc.gnu.org/ml/libstdc++/2017-11/msg00112.html