Switch default console tty from /dev/console to /dev/constty

With this switch processes (such as xconsole) can open /dev/console
without breaking login on the text or serial console. This can be
trivially triggered by enabling xdm in rc.conf and hitting
Ctrl+Alt+F1 or equivalent once booted.

The changes:
- Add entry for /dev/console or /dev/constty if missing
- If a port's had /dev/console 'on' switch it off and enable /dev/constty
- If a port did not have /dev/console 'on', leave /dev/constty off

Some ports had /dev/console off and /dev/ttyE0 enabled, presumably to
avoid just this issue. It may make sense to adjust these also (but not
in this pass)

As discussed on current-users

branches: 1.20.34; 1.20.36;
Per discussion on tech-userlevel, finally fix PR 10127:
move all ttyE* entries that use "vt100" emulation to wsvt25 term type.
The terminfo vt220 entry lacked (correctly) a delete key entry, which
was a regression against the netbsd-5 termcap entry. On the other hand,
only a very small number of foreign systems lacks support for wsvt25
nowadays.

branches: 1.19.18; 1.19.20;
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: 1.18.26;
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.

Back out last change as suggested by Hubert Feyrer in private e-mail:
The "ttys" file is modified by "sysinst" during installation.

Enable for "getty" processes because because the i386 port used wscons(4)
default these days and the default "wsconf.conf" creates four screens.

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

Do what we should have been doing long ago; use /dev/console by default as the
boot console tty, so that the console is on the same place that the kernel
dmesg output goes, whether wscons or serial. Users who want to use tty00
or ttyE0 explicitly can change /etc/ttys themselves.

Also use "vt100" as terminal type for /dev/console (for a reasonable baseline
that also works with wscons; pccons is long since no longer default).

This addresses PR install/13249, i386-specific, but may be appropriate to
apply to all ports.

This should be the final part of moving to 64 PTYs by default. Added
entries for tty{r,s}{0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f} to /etc/ttys.

Thanks to Matthew Green for pointing out the need.

branches: 1.10.8;
turn off ttyE[123] by default -- default installs don't configure them.

branches: 1.9.2;
wscons is default now - replace the "ttyv0" getty by a number of
"ttyEn" lines.
Thanks to "Johnny C. Lam" <lamj@stat.cmu.edu> for pointing out.

RCS ID police

Change vga to ttyv0, with a symlink for X.

branches: 1.6.2;
reality

changes from 0.9-ALPHA2 to 0.9-BETA

branches: 1.4.2;
Remove a spurious `unknown' that was screwing people over.

changes for init...

changed `console' to `vga'

branches: 1.1.1;
Initial revision