[clang] [CIR] Lowering __builtin_stdc_* calls (PR #214931)

[Bruno Cardoso Lopes via cfe-commits]

bcardosolopes wrote:

@xakep8 does this requirement below applies?

> We only require contributors to have a public email address associated with their GitHub commits

If so let me know and I'll land for you! Thanks for the contribution

https://github.com/llvm/llvm-project/pull/214931