C++17

[Mojca Miklavec]

Hi,

What's the up-to-date recommendation for ports requiring C++17?

There were several different approaches, some of them probably still
in PR queue, and I kind of lost track about what a port should do now
to minimize the effort & copy-paste errors, both now and in the
future.

(I would like to avoid the error-prone process of manually
blacklisting a zillion of compilers in each individual port.)

Thank you,
    Mojca