//sys	Fsync(fd int) (err error)
//  Fsync is not called for os.File.Sync(). Please see internal/poll/fd_fsync_darwin.go
//sys	Ftruncate(fd int, length int64) (err error)
//sys	Getdtablesize() (size int)
//sysnb	Getegid() (egid int)
//sysnb	Geteuid() (uid int)
//sysnb	Getgid() (gid int)
//sysnb	Getpgid(pid int) (pgid int, err error)
//sysnb	Getpgrp() (pgrp int)
//sysnb	Getpid() (pid int)