44de2bb694
Introduce a cmake variable that guards the inclusion of ClangIR into the build of clang. Guard that we aren't trying to build without MLIR. Add two subdirectories that, as of now, don't do anything. Reviewers: bcardosolopes, erichkeane, petrhosek, Ericson2314 Reviewed By: bcardosolopes Pull Request: https://github.com/llvm/llvm-project/pull/86078