- llvm10 in FreeBSD before r364284 miscompiles virtualbox 6.1 causing errors.
- llvm15 in FreeBSD miscompiles virtualbox 6.1 causing errors: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=270189.
Force llvm14 from ports. Use VBOX_LLVM_VER in make.conf to define different llvm.
Tested build on 12.4, 13.1, 13.2, but I don't have 14 for test build and run.