Merge "Make it easier to add new build architectures" am: 4c73e92a71 am: 380f285f16 am: b5a457cdfc

Original change: https://android-review.googlesource.com/c/platform/external/webrtc/+/2449947

Change-Id: Ibca62b1c69d4d643cc235ee1350e1857fd83b425
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>