fix build error with boost 1.59
fix build error with boost 1.59

bitsuperlab/cpp-play,dacsunlimited/dac_play,dacsunlimited/dac_play,bitsuperlab/cpp-play,dacsunlimited/dac_play,bitsuperlab/cpp-play,bitsuperlab/cpp-play,dacsunlimited/dac_play,dacsunlimited/dac_play,dacsunlimited/dac_play,bitsuperlab/cpp-play,bitsuperlab/cpp-play