Multihead updates

[James S. <jsi...@su...>]

Hi folks!

  Just to let you know I made it so mdacon and vgacon can exist at the
same time. The only problem which I just tracked down is only the first vc
works for the second head which is mdacon. I tracked the problem down to
tty->winsize not being allocated. con_open assumes it already is but it
seems the tty layer does allocate it before hand :-( I will probe tomorrow
to find a solution.