The end of CONFIG_ANDROID

This is the correct answer indeed.

FYI, before Corbet asked about this in that thread, somebody posed the same question with a bit more thoughtfulness on the WireGuard mailing list:

https://lore.kernel.org/wireguard/CAHmME9p2OYSTX2C5M0faKt...

If various people in these comments think they have worthwhile alternative ideas for this, that might be a good thread to jump in on and propose patches or different algorithms or whatever else.