c: -Wincompatible-pointer-types should cover mismatches in ?:

gcc/c/

	PR c/109826
	PR other/44209
	* c-typeck.cc (build_conditional_expr): Use
	OPT_Wincompatible_pointer_types for pointer mismatches.
	Emit location information for the operand.

gcc/testsuite/

	* gcc.dg/Wincompatible-pointer-types-2.c: New.
	* gcc.dg/Wincompatible-pointer-types-3.c: New.
	* gcc.dg/Wincompatible-pointer-types-4.c: New.