* configure.in: add DBUS_BINDIR as a #define to C source code.

	* configure.in: add DBUS_BINDIR as a #define to C source code.

	* tools/dbus-launch.c
	* tools/dbus-launch.h
	* tools/dbus-launch-x11.c:
	* tools/dbus-launch.1: Add the --autolaunch option to
	dbus-launch, which makes it scan for an existing session
	started with --autolaunch. With that option, it also creates
	an X11 window and saves the bus address and PID to it.

	* dbus/dbus-sysdeps.h:
	* dbus/dbus-sysdeps-unix.c (_dbus_get_autolaunch_address): Add
	a function that runs "dbus-launch --autolaunch" to retrieve
	the running D-Bus session address (or start one if none was running)

	* dbus/dbus-transport.c: Add the handler for the "autolaunch:"
        address protocol, which tries to get the running session from
        dbus-launch.

	* dbus/dbus-bus.c:
	* dbus/dbus-internals.h: Make "autolaunch:" be the default
	D-Bus session bus address.

	* dbus/dbus-connection.c: Fix horrible typo in error message.