Upgrade gcc.

I know, it's not the answer you want, but 7.2 was released August 14, 2017, and we're now requiring C++17 and using it more and more intensively. We're not entirely sure where the cutoff should be, but you've just proven it's after 7.2. We're not going to spend time supporting borderline compilers (or OSes, I'm looking at you OSX < 10.14).

Last edited by Olivier Galibert; 01/05/21 12:45 PM.