+ /* FIXME: technically, the type of n1 should be `unsigned int',
+ but that evokes an unsuppressible warning from gcc-4.0.1 and
+ older. If gcc ever provides an option to suppress that warning,
+ revert to the original type, so that the test in xalloc_oversized
+ is once again performed only at compile time. */
+ size_t n1 = n0 + 1;