autolaunch uuid support

[Havoc Pennington]

Thiago Macieira wrote:
> Havoc Pennington wrote:
>>   - an implied option --use-existing means try to read an existing bus
>>     from in order 1) DBUS_SESSION_BUS_ADDRESS 2) the display
>>     and prefer these to launching a new bus. libdbus
>>     may need to unset DBUS_SESSION_BUS_ADDRESS before
>>     exec'ing dbus-launch.
> 
> Why would it need to unset? I don't get it.
> 

My thought was that if the session bus address is "autolaunch:" (or 
"foobar:,autolaunch:" then in resolving autolaunch: libdbus should 
launch a new bus (or read from the X selection) rather than just return 
"foobar:,autolaunch:" again.

Not sure how all the details work out though.

Havoc