CHANGED
#define CHANGED(n,o,f) ((n)->f != (o).f)
#undef CHANGED
#define CHANGED(x) ((int)(x) != -1)
#undef CHANGED
#define CHANGED(a, t) (vap->a != (t)VNOVAL)
if (CHANGED(va_atime.tv_sec, time_t) ||
if (CHANGED(va_flags, u_long)) {
#undef CHANGED
#define CHANGED 01 /* low bit is used to show modification */