* test/unused-code-gc.py: hacky script to find code that's used
	only by the bus (not libdbus) or used only by tests or not used at
	all. It has some false alarms, but looks like we can clean up a
	lot of size from libdbus.

	* dbus/dbus-sysdeps.c, dbus/dbus-sysdeps-utils.c,
	dbus/Makefile.am: initially move 10K of binary size out of libdbus