Bug#942558: hurd: should return ENXIO instead of EIEIO in open()
Control: affects -1 s6
When calling open(fifo_fd, O_WRONLY | O_NONBLOCK) on an fifo file, which has
no reader, it should return ENXIO. But on Hurd, it returns EIEIO.
This causes s6 failed to start, as it expects an ENXIO.
The behaviour should be consistent with
> O_NONBLOCK is set, the named file is a FIFO, O_WRONLY is set,
> and no process has the file open for reading.
 it was discussed at