Policy based on active VT

[Artem Kachitchkine]

Just want to note that it's a subset of a more generic problem to support HAL 
applications in multi-seat configurations, which can take various forms from 
per-user-assigned USB hub ports to thin clients like Sun Ray to sandbox 
environments like Jails or Zones. It's a subset in the sense that "same user on 
multiple VTs" is a special case of "different users on multiple terminals of 
arbitrary types". One could look at implementing a subset either positively 
(small step in the right direction) or negatively (but do we have a long-term 
vision), depending on the POV.

As part of HAL port to Solaris we're thinking about some extensions to HAL and 
D-BUS, which of course will be open sourced, though there's no guarantee that 
they will be accepted upstream.

-Artem.