Compile error when try to use firebase::database::Database #6

My project uses firebase auth, database. When i tried to call the entry point for the Firebase Realtime Database C++ SDK, something like that
auto database = ::firebase::database::Database::GetInstance(firebase::App::GetInstance());

I should get these errors when compile on android

`[armeabi] Gdbserver : [arm-linux-androideabi-4.9] libs/armeabi/gdbserver
[armeabi] Gdbsetup : libs/armeabi/gdb.setup
[armeabi] SharedLibrary : libMyGame.so
firebase/database/client/cpp/src/android/database_android.cc:131: error: undefined reference to 'firebase::FutureManager::FutureManager()'
firebase/database/client/cpp/src/android/database_android.cc:309: error: undefined reference to 'firebase::FutureManager::~FutureManager()'
firebase/database/client/cpp/src/android/database_android.cc:309: error: undefined reference to 'firebase::FutureManager::~FutureManager()'
firebase/database/client/cpp/src/android/database_reference_android.cc:115: error: undefined reference to 'firebase::FutureManager::ReleaseFutureApi(void*)'
firebase/database/client/cpp/src/android/database_reference_android.cc:86: error: undefined reference to 'firebase::FutureManager::AllocFutureApi(void*, int)'
firebase/database/client/cpp/src/android/database_reference_android.cc:99: error: undefined reference to 'firebase::FutureManager::MoveFutureApi(void*, void*)'
firebase/database/client/cpp/src/android/database_reference_android.cc:105: error: undefined reference to 'firebase::FutureManager::MoveFutureApi(void*, void*)'
firebase/database/client/cpp/src/android/database_reference_android.cc:76: error: undefined reference to 'firebase::FutureManager::AllocFutureApi(void*, int)'
firebase/database/client/cpp/src/android/database_reference_android.cc:475: error: undefined reference to 'firebase::FutureManager::GetFutureApi(void*)'
firebase/database/client/cpp/src/android/disconnection_android.cc:48: error: undefined reference to 'firebase::FutureManager::AllocFutureApi(void*, int)'
firebase/database/client/cpp/src/android/disconnection_android.cc:56: error: undefined reference to 'firebase::FutureManager::ReleaseFutureApi(void*)'
firebase/database/client/cpp/src/android/disconnection_android.cc:236: error: undefined reference to 'firebase::FutureManager::GetFutureApi(void*)'
firebase/database/client/cpp/src/android/query_android.cc:135: error: undefined reference to 'firebase::FutureManager::ReleaseFutureApi(void*)'
firebase/database/client/cpp/src/android/query_android.cc:90: error: undefined reference to 'firebase::FutureManager::AllocFutureApi(void*, int)'
firebase/database/client/cpp/src/android/query_android.cc:117: error: undefined reference to 'firebase::FutureManager::MoveFutureApi(void*, void*)'
firebase/database/client/cpp/src/android/query_android.cc:124: error: undefined reference to 'firebase::FutureManager::MoveFutureApi(void*, void*)'
firebase/database/client/cpp/src/android/query_android.cc:640: error: undefined reference to 'firebase::FutureManager::GetFutureApi(void*)'
collect2: error: ld returned 1 exit status
make: *** [obj/local/armeabi/libMyGame.so] Error 1
Error running command, return code: 2.

If i comment out that line, everything goes right.