Linux stat(2) and friends return more fields than the
ones described in the manual page.  The "hidden" fields
are:

    struct timespec st_atim;            /* Time of last access.  */
    struct timespec st_mtim;            /* Time of last modification.  */
    struct timespec st_ctim;            /* Time of last status change.  */

with the following macros defined for backwards compatibility:

# define st_atime st_atim.tv_sec
# define st_mtime st_mtim.tv_sec
# define st_ctime st_ctim.tv_sec

The guestfs_stat, guestfs_lstat and guestfs_lstatlist calls
do not allow us to return these fields.

This also means that guestmount (ie. FUSE) cannot show nanosecond
timestamps.