Sync AnyEvent timer (brutal way) if timeskew more than 60 seconds.

AnyEvent does not sync its timers with system time, so cron jobs that
scheduled for particular time, shoots with time skew after wakeup from
hibernate or suspend. And AnyEvent have no mechanism to sync its timers
with local system time. The only way to "sync" timers is to remove and
re-add watchers, so timers begin count time from beginning.

To workaround timekeeping issue for AnyEvent::Timer::Cron let's add
another time-based call back that will send SIGHUP to script if local
system time differs from time counter more than 60 seconds. SIGHUP
should trigger signal handler that remove all event watchers, re-read
config and re-add event watchers effectively reloads config and re-launch
timers for AnyEvent.

i3status-anyevent

@@ -40,6 +40,9 @@ my $i3 = i3 ();
 my $done = AnyEvent->condvar;
 $i3->connect->recv or die 'Unable to connect to i3';
 
+# Local Time Counter
+my $TC = time();
+
 # event pool
 my @EP;
 
@@ -758,6 +761,20 @@ sub add_events () {
 				}
 			)
 		}
+
+		# also we need workaround for timers after sleep or hibernate
+		push @EP, AnyEvent->timer (
+			after    => 60,   # first invoke after 1 minute
+			interval => 60,   # then invoke every 1 second
+			cb       => sub { # the callback to invoke
+				$TC = $TC + 60;
+				my $timeskew = $TC - time ();
+
+				if (($timeskew > 60) || ($timeskew < -60)) {
+					kill 'HUP', $$;
+				}
+			}
+		);
 	}
 
 	return;