PR c/64440
	* c-common.c (c_fully_fold_internal): Warn for division and modulo
	if orig_op1 isn't INTEGER_CST, op1 is INTEGER_CST and is zero.

	* gcc.dg/pr64440.c: New test.
	* c-c++-common/pr56607.c: Don't limit dg-warnings to C++.

From-SVN: r219279