That sounds like a big issue. I’ll look over it but I can’t promise that it’ll work. I don’t have a mac myself and i’m not too familiar with the software.
Willing to help test/debug. Quick search yielded this GitHub issue that might help:
https://github.com/renpy/renpy/issues/266
I'll try to reproduce with a renpy snippet when I get to a computer.
Giving a quick update: this is going to be slightly more complicated than I thought.
I'm assuming you're working off of the code that was provided from this Reddit thread: https://bit.ly/2Hsdp1d
If so, then the big thing to figure out is how to replicate the file structure of Doki Doki Literature Club (DDLC). As it currently stands, that piece of code will try to look inside the .app file for the Mac, whereas you want the file to be generated on the same level as the .app file. This means that you'll want to replicate the file structure of DDLC. A quick examination on Steam shows that it packages a .app file separately from the rest of its scripts and resources, so that way basedir will be able to find the .app file. Maybe someone who is more proficient with Ren'py can help with this, as it seems like a potential paradigm that can be repeated for file distribution. Otherwise, I'll try taking a stab at this later.
Turns out there was one last issue:
https://github.com/renpy/renpy/issues/1326
It seems that by default, there's an issue with how macOS deals with file attributes. I followed the terminal command to clear the folder attribute for it to launch, otherwise it crashes upon launch.
If you're able to do that before distribution, that should help with this last problem. Otherwise I can provide a zip with my modifications so that you can distribute that version.