* cppinit.c (cpp_cleanup): Free include dir chains.
	* cpplib.c (do_undef): Let _cpp_free_definition make the node void.
	(do_unassert): Free the assert with _cpp_free_definition.
	* cppmacro.c (_cpp_free_definition): Free memory allocated for
	assertions.  Make the node a T_VOID node.

From-SVN: r35765