src/mongo/util/fast_clock_source_factory.cpp:46:9: warning: moving a temporary object prevents copy elision [-Wpessimizing-move]
        std::move(stdx::make_unique<SystemClockSource>()), granularity);
        ^
src/mongo/util/fast_clock_source_factory.cpp:46:9: note: remove std::move call here
        std::move(stdx::make_unique<SystemClockSource>()), granularity);
        ^~~~~~~~~~                                      ~
1 warning generated.