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

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

Change-Id: Ie26ad79492153702cccd6cee0b60599cdfdbea3b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>