vonT, try reading through again the introductory section of the GitHub page where you downloaded the project: GitHub TCB. The reason Arduino is giving you errors when compiling is that it thinks you are trying to compile for the "Genuino Uno" board, but the code is designed for the TCB board. The TCB is based on the Arduino Mega board which uses a different processor. So in the Arduino IDE go to the Tools menu, then Boards, then select Arduino Mega, and it should compile. [/li][/list]
As for inserting hyperlinks into your posts - for security reasons this forum (and all other forums) ignore HTML. Instead the forum uses something called BBC, which stands for Bulletin Board Code. So rather than using html tags, to insert a hyperlink do this instead: Google. Then the forum will render it as Google.
Download and compile OPConfig source code to review from GitHub: Still looking around for my old Qt license!
If you don't mind sharing I'd be curious to know what sort of embedded work you have done. With any sort of formal education, or even just the long experience you possess, my coding practices may seem unusual - or maybe not, I guess I don't know. I often wonder if I've missed context, perspective or sense of proportion from self-education, but it's hard to know what you missed if you don't what you missed!
Whew! I had forgotten how long it took to install the Qt IDE! .
Today it developed a strange mechanical "squelch" when turning left.