Merge "floss: use pkg-config for linking protobuf and flatbuffers" into main...

Merge "floss: use pkg-config for linking protobuf and flatbuffers" into main am: 12e4368b am: 6684da78 am: 921fca74

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Bluetooth/+/2800113



Change-Id: Id986697fa306a053a3dc7e0c739f3e9159335f81
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>