LLVM 16 supports Crystal's DWARF5 language code

[HertzDevil]

LLVM 16.0.0-rc4 is about to be released. Getting Crystal to work on LLVM 16 is a walk in the park compared to LLVM 15, as it requires just minor changes to src/llvm/ext/llvm_ext.cc for C++17 compatibility.

However, this PR caught my attention: https://github.com/llvm/llvm-project/commit/b70bbaaaa9d9a230f45453b4d792637ee19c0ddc. It means that, for the first time, debug information produced by Crystal no longer needs to share the same language code as C++. It doesn't seem anything is in place for LLDB 16 though.

We should spend some time to investigate the impact this has on our native debugging capabilities. Perhaps this will finally enable us to contribute Crystal-specific patches to LLDB itself?