typeck.c (build_binary_op_nodefault): Warn on use of NULL in arithmetic.

typeck.c (build_binary_op_nodefault): Warn on use of NULL in arithmetic.

	* typeck.c (build_binary_op_nodefault): Warn on use of NULL in
	arithmetic.
	* except.c (build_throw): Warn when NULL is thrown, even with
	-ansi.  Use ansi_null_node, rather than integer_zero_node, in the
	thrown expression.

From-SVN: r21863