PR c/25309
	* c-common.c (complete_array_type): Diagnose too-large arrays and
	set type to error_mark_node.

testsuite:
	* gcc.dg/large-size-array-2.c: Expect diagnostic for too-large
	array.
	* gcc.dg/large-size-array-4.c: New.  Copy of large-size-array-2.c
	without -O2.

From-SVN: r128811