Server refused to allocate pty

Debian升级到unstable，xterm无法运行
系统竟然不自动修改fstab
Glibc 2.1 has the support for new pty system. I had the same problem.
>From Chages file in 2.2.x kernel:
   Optional support for Unix98 pty devices has also been added. If you
   want to use the Unix98 ptys, you should be running at least
   glibc-2.0.9x, and you must switch completely to Unix98 pty's.  The
   general procedure for configuring Unix98 pty support is:

   - Compile your kernel with CONFIG_UNIX98_PTYS and CONFIG_DEVPTS_FS.
   - mknod /dev/ptmx c 5 2
     chmod 666 /dev/ptmx
     mkdir /dev/pts           
   - Add to /etc/fstab:

     none            /dev/pts        devpts        gid=5,mode=620    0 0

     (Note:  gid=5 is applicable for RedHat systems for which group "tty" has
     gid 5.  Adjust according to your distribution.  Use mode=600 if you want
     "mesg n" to be default.)
   - Mount /dev/pts