fixed build error on Mac OS X
fixed build error on Mac OS X

UCASREN/pyenv,syndbg/goenv,VShangxiao/pyenv,rowhit/pyenv,pyenv/pyenv,syndbg/goenv,fly19890211/pyenv,lozybean/pyenv,syndbg/goenv,syndbg/goenv,blueyed/pyenv,lepture/pyenv,kevinburke/pyenv,fly19890211/pyenv,takluyver/pyenv,dnsd/pyenv,sebhahn/pyenv,genome-vendor/pyenv,sebhahn/pyenv,yeonsh/pyenv,dongguangming/pyenv,takluyver/pyenv,habinmusic/pyenv,VShangxiao/pyenv,obimod/pyenv,yeonsh/pyenv,lepture/pyenv,UCASREN/pyenv,pyenv/pyenv,zmwangx/pyenv,zmwangx/pyenv,cehoffman/pyenv,cehoffman/pyenv,hlecuanda/pyenv,xshwy/pyenv,genome-vendor/pyenv,BanzaiMan/pyenv,dnsd/pyenv,recruit-mtl/pyenv,kevinburke/pyenv,yyuu/pyenv,recruit-mtl/pyenv,obimod/pyenv,BanzaiMan/pyenv,yyuu/pyenv,xshwy/pyenv,sebhahn/pyenv,hlecuanda/pyenv,chenfengyuan/pyenv,dongguangming/pyenv,habinmusic/pyenv,pyenv/pyenv,chenfengyuan/pyenv,lozybean/pyenv,rowhit/pyenv