[clang] [llvm] [IR][clang][CodeGen] Introduce `!llvm.errno.tbaa` for errno alias disambiguation (PR #125258)

[Nikita Popov via llvm-commits]

nikic wrote:

Could you please split off the remaining llvm/ changes in this PR? Then this one just emits the metadata and updates tests.

https://github.com/llvm/llvm-project/pull/125258