Merge "Add exported_c_header_dir config option." into main am: 6ed7797cba

Original change: https://android-review.googlesource.com/c/platform/development/+/2832836

Change-Id: I1d29bd68ca89c64e6882fd2b64b7f4e8be479342
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>