It seems that there is an include file for gtty and stty but when I 
   compile a program using it I get undefined _gtty or _stty.  There is also
   a manual entry for gtty and stty which seems to indicate they should be 
   there.

Did you *read* the man page?!?!  I quote:

     These interfaces are obsoleted by ioctl(2).  They are available from the
     compatibility library, libcompat.

And they are definitely in libcompat on my machines.


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