Thanks, Willem.
Exciting, I got Linphone working on my main PC.
The solution was that I had to have it in the exact same directory as it was on the system where it was built. If I do that, I don't have to do any other steps.
So for now, I must run linphone from here:
/home/mark/temp/linphone-desktop/OUTPUT/desktop/bin
It would be nice to know if it is possible to have it run from another folder without having to built it again, but for now I'm up and running. I also got it talking to Asterisk properly. Next is trying to enable G729.
Thanks again,
Mark