macOS build confines mouse after being minimized #266
Description
When the mouse confinement mode is set to window, if you minimize the client with F4 (either while fullscreen or windowed), the mouse will continue to be confined to the previous game viewport and you have to "break free". This is most noticeable when you're either running with dual displays (so that you're unable to move the mouse to the second display) or when running in a lower resolution or windowed mode. This was tested on macOS 10.15. Note that this occurs both with the official 2.4.20 release and with the SDL2 fixes in PR #251.