[issue1485] getty doesn't work on serial port

[Jordan Gordeev]

Matthew Dillon wrote:
:New submission from Hasso Tepper <hasso at estpak.ee>:
:
:Getty doesn't work on serial port any more. It certainly did some months ag=
:o=2E
    I tested this with the latest master and it does work but it must
    be enabled in /etc/ttys.
getty does indeed work, but usually you can't log in because it's stuck 
on ttyhup wait channel, or because login gets stuck on ttydcd.
Observed behaviour indicates it's a race in the kernel. Before devfs 
everything worked fine.