Now I know the recommendation is to use Xcode 13.2, but like an idiot I allowed macOS to update Xcode before checking with the forum. So now I've got Xcode 13.3.1 installed, which can't compile from B4i without errors. (This is the error.)
So I have two questions:
1. Did anyone find a simple and reasonable way to make 13.3.1 work with B4i?
2. How do I download Xcode 13.2? The built-in App Store doesn't seem to give the option. I've found https://developer.apple.com/download/release/, but it also doesn't give the option to download old versions.
After I installed 13.2 and did the xcode-select to point to it, I got a different error in the builder log, which gave me a clear indication to what the problem was: The IDE was connected to the Simulator.
I swapped the IDE to a non-existing IP address (because there is neither a way to see what device the B4i IDE is connected to, nor a way to cleanly disconnect), reset xcode-select to 13.3, restarted the builder and tried again. Worked just fine.