Merge "Export clang header for the build-tools sdk-repo build" am: def3a7e40a am: dcd0be3ce5 am: 4bb41194e5 am: 70a1fcf5cb

Original change: https://android-review.googlesource.com/c/platform/external/clang/+/1828413

Change-Id: Icb5b374cd12a0839e12843f76b5b8bd9ad88e478