Not able to run .sh file using subprocess (PermissionError: [Errno 13])

Hey everyone! Fairly new to github and streamlit so I’ve been running into issues.
So I’m currently building an app that runs off of an engine I’ve written in C++. I’ve used streamlit in python for the user to be able to communicate with the engine. However, this required me to create a wrapper which is then subsequently used to create a .so file. The .so file will have to be created when the program runs because the architecture of my system is most definitely different from the architecture of the servers that streamlit community cloud runs on. I’ve made accommodations for this in my code like this:

However, it gives me the following error in the terminal:
PermissionError: [Errno 13] Permission denied: 'build/build.sh'

I realise that my program may not have the permission to run a .sh file. Is that the case? If so, is there any other way I can create a .so file?

Here’s the github to my project.
Here’s the streamlit app.

Thank you!