[gnome-calendar/gnome-3-36] calendar-monitor: Fix critical in finalize

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 1d464c08314834184ed32dd52e7c24e4fdae6892
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Wed Apr 1 20:26:54 2020 -0500

    calendar-monitor: Fix critical in finalize
    
    self->thread can be NULL if gcal_calendar_monitor_set_range() was never
    called prior to finalize. This is fine, so just check for NULL here
    using g_clear_pointer().

 src/core/gcal-calendar-monitor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/core/gcal-calendar-monitor.c b/src/core/gcal-calendar-monitor.c
index 87172e78..8055eead 100644
--- a/src/core/gcal-calendar-monitor.c
+++ b/src/core/gcal-calendar-monitor.c
@@ -996,7 +996,7 @@ gcal_calendar_monitor_finalize (GObject *object)
 
   g_cancellable_cancel (self->cancellable);
   notify_view_thread (self, QUIT);
-  g_thread_join (self->thread);
+  g_clear_pointer (&self->thread, g_thread_join);
 
   remove_all_events (self);