AC_DEFUN([AC_STRUCT_ST_MTIM_NSEC],
[AC_CACHE_CHECK([for nanoseconds member of struct stat.st_mtim],
ac_cv_struct_st_mtim_nsec,
[ac_save_CPPFLAGS="$CPPFLAGS"
ac_cv_struct_st_mtim_nsec=no
for ac_val in tv_nsec _tv_nsec st__tim.tv_nsec; do
CPPFLAGS="$ac_save_CPPFLAGS -DST_MTIM_NSEC=$ac_val"
AC_TRY_COMPILE([ [ac_cv_struct_st_mtim_nsec=$ac_val; break])
done
CPPFLAGS="$ac_save_CPPFLAGS"])
if test $ac_cv_struct_st_mtim_nsec != no; then
AC_DEFINE_UNQUOTED(ST_MTIM_NSEC, $ac_cv_struct_st_mtim_nsec,
[Define to be the nanoseconds member of struct stat's st_mtim,
if it exists.])
fi
]
)