I had a working environment with builds of MySQL using Mac OS X 12.0.1 and Xcode 13.0. The environment built ARM64 binaries.
After upgrading to Mac OS X 12.1 and upgrading Xcode to 13.2 I can still compile those trees that have already executed Cmake.
But if I build a directory from scratch using cmake, I get an error that says that I can't include ARM64 libraries into an x86_64 build. So for some reason the builds have changed to building x86_64 instead of ARM64 which is a bit annoying to say the least.
The binaries that was built before the error are reported as x86_64 binaries.