re PR c++/48029 (ICE in finish_member_declaration() with --param ggc-min-expand=0 --param ggc-min-heapsize=0)

	PR c++/48029
	* stor-layout.c (layout_type): Don't set structural equality
	on arrays of incomplete type.
	* tree.c (type_hash_eq): Handle comparing them properly.
	* cp/pt.c (iterative_hash_template_arg): Remove special case for
	ARRAY_TYPE.

From-SVN: r170853