x_destroy
void (*x_destroy)(struct __rpc_xdr *);
if ((xdrs)->x_ops->x_destroy) \
(*(xdrs)->x_ops->x_destroy)(xdrs)
if ((xdrs)->x_ops->x_destroy) \
(*(xdrs)->x_ops->x_destroy)(xdrs)
ops.x_destroy = x_destroy;
static void x_destroy(XDR *);