Merge "Export build flags to soong." into main am: 1acc860f am: 6ff33725

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



Change-Id: Iac2b1ebf70044c8474ed2e698eac333e5c35f9c6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>