There have been multiple reports of Xcode 14.0 (based on upstream LLVM
14) segfaulting when compiling `LibCore/Process.cpp`. Let's require
Xcode 14.3, which is a known good version based on LLVM 15.
Note that Xcode 14.3 requires macOS Ventura, so users of Monterey or
older are expected to get Homebrew Clang instead.
Homebrew Clang 13 also suffers from the same crash. Although I have not
tested on Linux, the backtrace points to the middle-end, so x86_64 is
also likely to be affected. LLVM 14 was released 14 months ago, so it's
not an unreasonable requirement.