* ch-exp.y (literal): Recognize NULL.

	* ch-exp.y (literal):  Recognize NULL.
	(tuple):  Parse simple unlabelled tuples.
	* eval.c (evaluate_subexp case OP_ARRAY):  Use expect_type to
	evaluate brace-initializer-expressions depending on context.
	(evaluate_subexp case UNOP_CAST):  Pass the target type as
	expected type when evaluating the expression.