Recover from zero-length reads.

Rather than deactivating a device the first time it gets a zero-length read,
temporarily suppress waiting on it in the main select call and set a timeout
after which it will be un-suppressed. A zero-length read after unsuppression
will trigger deactivation.

All regression tests pass.

1 files changed, 2 insertions, 0 deletions

diff --git a/serial.c b/serial.c
index 499dd3cb..55f0c003 100644
--- a/serial.c
+++ b/serial.c
@@ -72,6 +72,8 @@ void gpsd_tty_init(struct gps_device_t *session)
     session->shmTimeP = -1;
 # endif	/* PPS_ENABLE */
 #endif /* NTPSHM_ENABLE */
+    session->zerokill = false;
+    session->reawake = 0;
 }
 
 #if defined(__CYGWIN__)