FASYNC
fp1->f_flag |= FASYNC;
fp->f_flag |= FASYNC;
fp->f_flag &= ~FASYNC;
if (i & FASYNC) {
int flgs = tmp & FASYNC;
atomic_or_uint(&fp->f_flag, FASYNC);
atomic_and_uint(&fp->f_flag, ~FASYNC);
#define FCNTLFLAGS (FAPPEND|FASYNC|FFSYNC|FNONBLOCK|FDSYNC|FRSYNC|FALTIO|\
{ FASYNC, 'I' },