1.sudo make install时提示：Privilege separation user sshd does not exist。解决办法：
修改/etc/passwd文件，在最后加入 sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
2.安装成功时启动（sudo /usr/local/sbin/sshd start）时提示：sshd re-exec requires execution with an absolute path。解决办法：
sudo chown root /var/empty
sudo chown 744 /var/empty
sudo ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key
sudo ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key
sudo /usr/sbin/sshd start