MacOS: Cannot launch Mapster32.app over Finder (closes immediately without any errors)

This is an odd one. First, it only occurs with Mapster32.app, and not EDuke32.app.

If one launches the application, it briefly appears to start, but closes shortly afterwards with no error messages or crashlogs. This occurs even when compiling with STARTUP_WINDOW=0, hence it appears to be unrelated to #114.

Even more strangely, launching it over lldb appears to work fine, and mapster32 will work as expected.

I have verified this problem on both a MacOS Catalina 10.15.5 VM as well as on a physical Mac.