[Bug libstdc++/71809] compile llvm3.8.0 failed by the libstdc++ of gcc6.1.0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71809

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
https://bugzilla.suse.com/show_bug.cgi?id=964143