so I learned
1- that xcrun is not needed, just cancel the dialog that comes up offering to install it
2-that it is better to load a sketch than it is to copy and paste
3-that the sketch works better if all the jumpers have been installed--somehow I missed one
4-and works even better if none of the jumpers are installed with cold solder joints!
bottom line, success--stepper motor is running now on upload from macintosh
That is great news. It's good to hear you got it working.
I am working on a new clock and decided that it would be nice to have a cleaner circuit board, so I had one built. It is smaller since it only needs 3 sockets. I may build a few of them and include a pre-programmed Arduino Nano so it is ready to run. Even the simple kit version would be cleaner soldering without jumper wires. It is still in the mid stage of development, and should be available soon.