Event loops on secondary thread on macOS

[MiKom]

In #85 @akreuzkamp implemented public event loop class.

It doesn't support event loop on secondary threads though as the macOS API we use for that is supposed to be executed only from the main thread:

// (in MacOSPlatformEventLoop::waitForEventsImpl() )
NSEvent *event = [NSApp nextEventMatchingMask:NSEventMaskAny untilDate:expiration inMode:NSDefaultRunLoopMode dequeue:YES];

And when you do it from another thread, you get an exception:

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'nextEventMatchingMask should only be called from the Main Thread!'

It seems that the new API for event loop for macs that can be used for multiple threads is https://developer.apple.com/documentation/corefoundation/cfrunloop?language=objc

Likely we need to use it. What implications does it have wrt window input etc. is beyond me though. Someone with more mac knowledge needs to take a look.

Here's my vibe-coded, ChatGPT-fueled attempt that fails the tests: MiKom@888b601

Maybe it will be useful for some exploration.

[zakalawe]

Yes CFRunLoop is the way to go, although 'new api' is funny :)

[MiKom]

The "Event loop on multiple threads" PR got in (#85). So if you have time, we're ready to extend it to macOS.