GitHub action fails when multiple files are committed at once

[funbeedev]

About Bug or problem
The GitHub action to execute changed files fails when more than one file needs to be checked. Because each file has a 'main' function the compilation fails.

Steps to reproduce
Commit more than one file to the repo
Allow GitHub action for executing modified file to run

Potential fix - handle case when multiple files are committed to allow GitHub action to execute each file. Add loop to check if each changed file is a C file and compile individually.