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

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



Change-Id: Ic17643c06edb3d3988bf6a09dbdc31d63004b0b6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>