re PR c++/42010 ([C++0x] ICE: lang_* check: failed in discriminator_for_local_entity, at cp/mangle.c:1581)

	PR c++/42010
	* cp-tree.h (DECL_DISCRIMINATOR_SET_P): New.
	* mangle.c (discriminator_for_local_entity): Check it.

From-SVN: r155007