bb3263d3e3 bitcoin-tidy: fix macOS build (Cory Fields)
Pull request description:
[LLVM uses these options](https://github.com/llvm/llvm-project/blob/main/llvm/cmake/modules/HandleLLVMOptions.cmake#L178) for building as well, so there's precedent.
Also fix the shared library extension which was incorrectly being set to dylib.
Thanks to jonatack for reporting and debugging.
ACKs for top commit:
jonatack:
ACK bb3263d3e3 tested with arm64 macos 13.5, llvm 16.0.6 and cmake 3.27.2
Tree-SHA512: de7bfd497f38f1565a14d217d0b057cbfa788bdda702b5942b7f0b55947ae5e1c05af13e7d6a073ed036bc4db57035868f180034508b6e084ab9b901a5baaf2f
An LLVM installation will have `llvm-config` available to query for
info. Ask it for the `--cmakedir`, and use that in our bitcoin-tidy
example, rather than listing multiple different (potential) paths per
distro/OS etc.
