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: 7f49d1a5

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



Change-Id: I7b03c0882fc09473cab6ba15d805657bb725010f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>