MacOS support: Graphic thread + Input/Window Event thread

[Ecconia]

MacOS throws a bunch of errors when trying to start it. Cause of windows being generated on some other thread. But when I move a bunch of these things over, I might get issues on windows.
-> I lack a testing device to improve the macOS support. If one of you has a mac, feel free to help.

[Ecconia]

Current state:
I currently have one thread for rendering and another one for window/input events.
I do this to reduce input-handling lags. If the FPS are too low for the inputs to be processed, the user (me) gets frustrated. See Minecraft for example. You cannot use commands to stop some lag origin, cause your client lags too much - yay. No go!

Issue:
From what I learned MacOS requires graphic and inputs to be processed on the main thread.
They do this to prevent developers from not handling the input thread, and thus enforcing a better user experience (since the input will always be handled).
So their enforced better user experience, would worsen the user experience of this project.

Action:
I will not take any action. There is currently exactly no MacOS user interested in the project. And changing the current input system to use one thread, is below my minimum acceptance level (level Minecraft).

If you know that I am wrong, and there is a way to use two different threads - please tell me how to do it, so that we can add MacOS support.

You are also free to do the code change to use one thread yourself and PR it, as long as there is a toggle for it. (Warning its a very simple process).