After a couple of hours work this evening (largely fixing errors in the distribution makefile) I successfully compiled Gnocl to run on my newly acquired Raspberry PI3. It was much, much easier than expected. No changes to the source code whatsoever.
I now need to create a download page from Sourceforge. Currently running Ubuntu Mate on my Pi. Very nice, very pleased. Much faster than my sturdy old 32-bit workhorse.
Here's a snippet from a screenshot.