[Bug libstdc++/66771] [5/6 Regression] -std=c++11 doesn't work

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66771

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think those are simply invalid uses of C++ (I've seen such instances in a few
packages).