I tried again on macos and I tried everything I found including your link. The strange thing is that I can run the pixilang.app manually but only not in terminal. What can be the problem? Is this happening also on your macos @alex?
seems to be a bug in the temp folder evaluation. In Sunvox.app when you try to edit a meta modul you get a warning with ".sunvox_prev_session.sunvox" can not be written. while this is a hidden file in tmp folder that does not hurt the permission to store hidden files there is not given by default and cumbersome to grant when you try to keep your code simple. Since 10.14 there came some extra restrictions because companies saved hidden files in tmp folders quite a lot, making debugging hard for users and opened pandora's box for malicious stuff. So either a proper filename or hidden file in a visible "~"/user folder works.
Easy fix, just make the filename visible with a prefix-name in the sundog code.
another issue can be the AVMediaType permission on macOS which is not granted by default and can not be given manually, either each session asks if the permission was given after it was triggered. Basically similar to iOS7.0++ since OSX 10.12++, officially since macOS 10.14 mandatory
Terminal apps can not circumvent this procedure unless you risk a permanent sandbox flag which the user can only get rid of by uninstalling.