uintmax_t fsu_blocks; /* Total blocks. */
uintmax_t fsu_bfree; /* Free blocks available to superuser. */
uintmax_t fsu_bavail; /* Free blocks available to non-superuser. */
+ int fsu_bavail_top_bit_set; /* 1 if fsu_bavail represents a value < 0. */
uintmax_t fsu_files; /* Total file nodes. */
uintmax_t fsu_ffree; /* Free file nodes. */
};