fix Linux build error
fix Linux build error

hholi/phd2,simonct/phd2,simonct/phd2,OpenPHDGuiding/phd2,EverettQuebral/phd2,olegkutkov/phd2guiding_crao,OpenPHDGuiding/phd2,olegkutkov/phd2guiding_crao,simonct/phd2,OpenPHDGuiding/phd2,OpenPHDGuiding/phd2,hholi/phd2,hholi/phd2,EverettQuebral/phd2,hholi/phd2,olegkutkov/phd2guiding_crao,EverettQuebral/phd2,EverettQuebral/phd2,EverettQuebral/phd2,olegkutkov/phd2guiding_crao,simonct/phd2,simonct/phd2,hholi/phd2,hholi/phd2,olegkutkov/phd2guiding_crao,OpenPHDGuiding/phd2,OpenPHDGuiding/phd2,simonct/phd2,olegkutkov/phd2guiding_crao,EverettQuebral/phd2