re PR c++/91110 (ICE: tree check: expected class 'type', have 'exceptional' (error_mark) in cp_omp_mappable_type_1, at cp/decl2.c:1421)

	PR c++/91110
	* decl2.c (cp_omp_mappable_type_1): Don't emit any note for
	error_mark_node type.

	* g++.dg/gomp/pr91110.C: New test.

From-SVN: r273248