# st_atimespec.tv_nsec - FreeBSD, NetBSD, if ! defined _POSIX_SOURCE
# st_atimensec - FreeBSD, NetBSD, if defined _POSIX_SOURCE
# st_atim.st__tim.tv_nsec - UnixWare (at least 2.1.2 through 7.1)
# st_birthtimespec - FreeBSD, NetBSD (hidden on OpenBSD 3.9, anyway)
# st_atimespec.tv_nsec - FreeBSD, NetBSD, if ! defined _POSIX_SOURCE
# st_atimensec - FreeBSD, NetBSD, if defined _POSIX_SOURCE
# st_atim.st__tim.tv_nsec - UnixWare (at least 2.1.2 through 7.1)
# st_birthtimespec - FreeBSD, NetBSD (hidden on OpenBSD 3.9, anyway)