After my genius idea to delete all stuff in this discussion, which only cause trouble and chaos, I figured out to do another attempt and post again. This is version 2 of the little app. The gui and commandline are streamlined into one app. The commandline options are flexible now and it supports a configuration file. Unfortunately in GUI mode only one patch file at a time is supported (but I think this is not a real issue and is a limitation in GUI only). And it can create output folders too. Updated the first post with all relevant information.
So with 4.4, most core and main packages installed, but there were a few that wouldn't. lr-stella, lr-pcsx-rearmed failed to build.
So in short - trying this is a mixed bag. Some things will build. Some things won't.
At least the raspberry pi image is a stable platform, but doing PC builds will always be a forever-forward moving target
@mitu Ah, that scuppers those plans then. I think I'll give this up as a failed experiment. I did manage to get Kodi to launch from my green button by importing psutil and check_output and changing the code to