Unbreak BSD: use qemu_fdatasync instead of fdatasync

Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

posix-aio-compat.c

@@ -138,7 +138,7 @@ static size_t handle_aiocb_flush(struct qemu_paiocb *aiocb)
 {
     int ret;
 
-    ret = fdatasync(aiocb->aio_fildes);
+    ret = qemu_fdatasync(aiocb->aio_fildes);
     if (ret == -1)
         return -errno;
     return 0;