[automerger skipped] Add build_flag_declarations module am: 0a9b643c -s ours

am skip reason: Merged-In I97eb864e2d84bc606fef7e9077554894338edaa0 with SHA-1 c6aef168 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/soong/+/27562186



Change-Id: I77071fb06dd2c077e5f0d72475587f522c7ee122
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>