I already have software which runs on mac, which can be driven by a main 'runner' script. However, I want the software to be packaged as a .app. On a mac, I can run 'platypus' (https://www.sveinbjorn.org/platypus), and it will create a very nice .app file, which calls that runner script as an entry point (exactly what I am trying to do). It's very simple to use.
The problem is, platypus itself only runs on mac, and I need to bundle this all together (create the .app), on a Linux machine.
Is there an alternative to Platypus, which accomplishes the same result (generates a .app, with a script as the entrypoint), but which you can build on Linux? Or, is anyone aware of up-to date tutorial which explains how to accomplish this manually (but on Linux)?
(I've seen this: How to build a dmg Mac OS X file (on a non-Mac platform)? but it is for dmg files, while I need a .app file. Also, I'm specifically curious about programs simple like Platypus is.)