is unlikely to be needed, but is supplied just in case.\r
*/\r
#define MMAP_FLAGS (MAP_PRIVATE)\r
-static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */\r
#define MMAP_DEFAULT(s) ((dev_zero_fd < 0) ? \\r
(dev_zero_fd = open("/dev/zero", O_RDWR), \\r
mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \\r