Got a new M series computer and have started trying to be productive.
Installed some things (Xojo, Xcode), copied stuff from current computer. Then, attempted to compile an iOS project. Got an unreadable error message (lines over lapping). Note that this compiles fine on the old computer.
Discovered that if you right-click on the message a copy option appears. Copied. Pasted message in to a just-installed BBEdit. The critical line is:
iOS 17.2 Platform Not Installed.
Went to Xcode Settings Platforms and downloaded the platform.
Things now work.
Hope this helps someone.