Fix compiler warnings and remove protoc binary (can't build with em)
Fix compiler warnings and remove protoc binary (can't build with em)

invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten,invokr/protobuf-emscripten