utils: let format_utc_offset handle microseconds

format_utc_offset can be called with the return value of
g_date_time_get_utc_offset returning microseconds in a gint64. It is
also still called with the return value of icaltimezone_get_utc_offset
in seconds. Deal with both.

https://bugzilla.gnome.org/show_bug.cgi?id=762438

src/gcal-utils.c

@@ -793,7 +793,7 @@ get_source_parent_name_color (GcalManager  *manager,
 }
 
 gchar*
-format_utc_offset (gint offset)
+format_utc_offset (gint64 offset)
 {
   const char *sign = "+";
   gint hours, minutes, seconds;
@@ -803,6 +803,10 @@ format_utc_offset (gint offset)
       sign = "-";
   }
 
+  /* offset can be seconds or microseconds */
+  if (offset >= 1000000)
+    offset = offset / 1000000;
+
   hours = offset / 3600;
   minutes = (offset % 3600) / 60;
   seconds = offset % 60;

src/gcal-utils.h

@@ -121,6 +121,6 @@ void            get_source_parent_name_color                    (GcalManager
                                                                  gchar                **name,
                                                                  gchar                **color);
 
-gchar*          format_utc_offset                               (gint                   offset);
+gchar*          format_utc_offset                               (gint64                 offset);
 
 #endif // __GCAL_UTILS_H__