WireGuard fails to build on CentOS 7.1908

[Jason A. Donenfeld]

Hey Dario,

I'm not super familiar with the RHEL release varieties. Maybe you or
somebody can clarify and help define how we'll approach it?

What we've done in the past is support whatever the "latest" RHEL
kernel is. IIRC, 7.6 was released not so long ago, and we did the
compat.h work on 7.6, and then dropped support for RHEL 7.5. It sounds
to me like what you're saying now is that 7.6 has already been
replaced by 7.7? Or there's a stable 7.6 and then an "in-development"
7.7 that is rolling? If it's the latter case, do you know if that's
widely used and worthwhile for us to support?

In other words, I'm not so sure of the RHEL landscape, but if you make
a description and argument for what we should support in WireGuard's
compat layer, as long as it's somewhat reasonable, I'm happy to
oblige.

Jason