Attempt auditing public API to remove all cases where a Unix
	function returns weird emulated goo to Windows. This probably
	breaks the bus daemon on Windows, to fix it again we may
	need to stop processing unix-specific config options on Windows,
	and may need to add Windows-specific public API or config options.

	* configure.in (LT_CURRENT, LT_AGE): increment current and age,
	to reflect added interfaces; should not break soname.

	* dbus/dbus-transport.c (_dbus_transport_get_is_authenticated): do
	not invoke unix user function on Windows. Kind of a hacky fix, but
	we don't want a "unix uid" leaking out on Windows.

	* dbus/dbus-connection.c (dbus_connection_get_socket): add new API
	to get the socket fd on Windows or UNIX
	(dbus_connection_get_unix_fd): make this always fail on Windows