Add a constty entry, marked 'off', with otherwise the same settings
as the console. Now when coming up in single user mode the tset in
/.profile can set the terminal type correctly.
Note: I believe constty should be 'on' and console 'off', but thats a
separate discussion

branches: 1.5.26;
remove ad-hok list of pty's from port tty files, and auto-generate it so
that it is consistent, and in the proper order.

Revert 'console' back to /dev/console (from /dev/constty)

Change 'console' login to use /dev/constty so that its output isn't
stolen by code that requests system messages using TIOCCONS.

Added ttyp[g-zA-Z] (bin/15594).

Added sun2 etc files.

Sync with HEAD.