2012-10-24  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR c++/54928
	* tree-diagnostic.c (maybe_unwind_expanded_macro_loc):
	Use diagnostic_append_note.
	* diagnostic.c (diagnostic_build_prefix): Make diagnostic const.
	(default_diagnostic_finalizer): Do not destroy prefix here.
	(diagnostic_report_diagnostic): Destroy it here.
	(diagnostic_append_note): New.
	* diagnostic.h (diagnostic_append_note): Declare.

From-SVN: r192786