Merge "rust: add aconfig_flag support" into main am: 5ada6c27

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2863750



Change-Id: Ide278450fa058b6dc565bff395f541dc7b574905
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>