PR c++-common/67882

	* c-family/c-common.h (fold_offsetof_1): Add argument.
	* c-family/c-common.c (fold_offsetof_1): Diagnose more invalid
	offsetof expressions that reference elements past the end of
	an array.

        * c-c++-common/builtin-offsetof-2.c: New test.

From-SVN: r229717