Clean up fallout on ILP32 from r229831.

Clean up fallout on ILP32 from r229831.

gcc/
	PR c++/67942
	* cp/init.c (warn_placement_new_too_small): Convert integer
	operand of POINTER_PLUS_EXPR to ssize_t to determine its signed
	value.

c-family/
        * c.opt (Wplacement-new): Add a period to the end of
        a sentence.

From-SVN: r229959