Fix compiler warning on Windows 64 bit: _init_pos_args() result type is

Py_ssize_t, not int

Modules/_ctypes/_ctypes.c

@@ -4054,7 +4054,7 @@ Struct_init(PyObject *self, PyObject *args, PyObject *kwds)
         return -1;
     }
     if (PyTuple_GET_SIZE(args)) {
-        int res = _init_pos_args(self, Py_TYPE(self),
+        Py_ssize_t res = _init_pos_args(self, Py_TYPE(self),
                                         args, kwds, 0);
         if (res == -1)
             return -1;