Include Flatbuffers as source when building for mobile
Include Flatbuffers as source when building for mobile

The mobile platforms do not include the dependencies as part of the package step, so what the previous build system did was just include flatbuffers source files directly in app, which will be duplicated here.

firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk