[wireguard-apple] [iOS] Running WireGuard on a simulator

[Neutron]

Jeff, thank you for the clarification on how a simulator operates compared to an
emulator. The difference was certainly blurry in my head. I did a little more
digging and it turns out

GOOS_iphonesimulator := ios

is not required when targeting an iOS12.0 simulator. I had initially run it with
iOS14.5. Perhaps this line can be useful in the Makefile once the project's iOS
version gets bumped. Still, I would like to know why this happens.

Just like before on iOS14.5, I'm having issues with creating/editing
configurations in the simulator, with log messages like:

Saving configuration failed: Error Domain=NEVPNErrorDomain Code=5 "IPC failed"

The message I'm getting may be just as well be unrelated, but a common theme I'm
seeing is that you can't get Network Extension providers to work on simulators.
This Eskimo fellow seems to have good insight on the matter.

https://developer.apple.com/forums/thread/46004?answerId=134358022#134358022

If it really can't run on a simulator at the moment, perhaps it would be useful
for other tinkerers to see this mentioned somewhere in the README with a brief
reasoning attached. It would be a time saver, especially for those of us who are
not iOS hackers.

Neutron