Merge "Export build flags to soong." into main am: 2ab031f4

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2803674



Change-Id: I4904c9cd21307c4d690f683b3c9c1ecdbc600052
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>