Thank you. That jogged my memory! What I had done before was run some kind of vm to do it. It might have been macports or fink. I will have to look into it. It was something along the lines given
here. I remember doing some twiddling to xcode to get it. I think I had it working, though maybe I just tried and never got anywhere. But you pointed me in the right direction.
It was a stupid (but innocent) question so thank you sincerely for being kind and patient enough to answer it, as always. Calibre is great, and you have done a superhuman job with it, as everyone knows, and I am a happy camper.