Merge "Export build flags to soong." into main am: 1acc860f83 am: 1030fb06f9 am: fee15f90cb

Original change: https://android-review.googlesource.com/c/platform/build/+/2795632

Change-Id: I25dd640feba7bd720f39957ba36ff888dd5caa61
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>