mc 4.6.0 subshell fix for FreeBSD 5.x

[Nerijus Baliunas]

Hello,

> > > Attached patch fixes subshell support for FreeBSD 5.x which has grantpt(3).
> > 
> > What kind of problem do you have?  Does your patch work with FreeBSD 4.x?
>
> Yes my patch works with FreeBSD 4.x.
> FreeBSD 4.x does not have grantpt(3) so BSD version of
> pty_open_master is compiled in from subshell.c.

BTW, I've just compiled mc cvs on FreeBSD 4.5, and subshell does not work -
I can see output of commands by pressing Ctrl-O, but I cannot enter commands.
Should it be so?

Regards,
Nerijus