With systemd-logind the dbus-core will be used for more then just config, so
it should be possible to build it even when using a non dbus dependent config
backend.
This patch also removes the config_ prefix from the dbus-core symbols.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Daniel Stone <daniel@fooishbar.org>
