linux_udev: Retry poll() on EINTR

The poll() syscall may temporarily fail when it is interrupted by a
signal; -1 is returned and errno is set to EINTR.

When this occurred, the udev event thread exited.

Instead, since this is a temporary failure, just try the call again.
<https://www.gnu.org/software/libc/manual/html_node/Interrupted-Primitives.html>

Signed-off-by: Romain Vimont <rom@rom1v.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

libusb/os/linux_udev.c

@@ -172,7 +172,11 @@ static void *linux_udev_event_thread_main(void *arg)

	usbi_dbg("udev event thread entering.");

	while (poll(fds, 2, -1) >= 0) {
	while ((r = poll(fds, 2, -1)) >= 0 || errno == EINTR) {
		if (r < 0) {
			/* temporary failure */
			continue;
		}
		if (fds[0].revents & POLLIN) {
			/* activity on control pipe, read the byte and exit */
			r = usbi_read(udev_control_pipe[0], &dummy, sizeof(dummy));

libusb/version_nano.h

@@ -1 +1 @@
#define LIBUSB_NANO 11156
#define LIBUSB_NANO 11157