John Baldwin db27a9dac7 Make it easier to add more ptys to the pty(4) driver:
- Use unit2minor() and minor2unit() to generate minor numbers to support
  unit numbers higher than 255.
- Use simple string operations on the 'names' array rather than hard-coded
  constants and switch statements so that more ptys can be added by simply
  expanding the 'names' array.

MFC after:	1 week
2007-11-08 15:51:52 +00:00
..
2007-11-07 20:12:21 +00:00