Tim the “easy way” to build firmware would be to set up An instance of Gitlab to serve as your local repo on the way up to github, then set up pipelines using the CI tools. I believe they have a prepackaged docker containerized version on top of a Linux (not sure which) that should let you also install the avr tools and whatnot you would need to crosscompile for various things. This will of course not save time in the near term, but would definitely pay off long term, if for no other reason than getting immediate feedback at commit time.
i’m investigating What it takes to get my own firmware building. So far gitlab is up and executing a pipeline on an instance with Arduino and gcc-avr installed, so the real trick at this point is figuring out what the Arduino build process does. I’m not very familiar with it.
success, I have Gitlab building my firmware. It’s a reasonably simple pipeline also.