utils: Remove gcal_set_date_time()

`g_set_date_time()` now exists.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/873>

src/utils/gcal-date-time-utils.c

@@ -23,31 +23,6 @@
 #include "gcal-context.h"
 #include "gcal-utils.h"
 
-/**
- * gcal_set_datetime:
- * @dest: location to a #GDateTime pointer
- * @src: (nullable): a #GDateTime
- *
- * Performs the same of g_set_object(), but with #GDateTime
- * instances.
- *
- * Returns: %TRUE if the value of @dest changed, %FALSE otherwise
- */
-gboolean
-gcal_set_date_time (GDateTime **dest,
-                    GDateTime  *src)
-{
-  if (*dest == src)
-    return FALSE;
-
-  gcal_clear_date_time (dest);
-
-  if (src)
-    *dest = g_date_time_ref (src);
-
-  return TRUE;
-}
-
 /**
  * gcal_date_time_get_days_in_month:
  * @date: a #GDateTime

src/utils/gcal-date-time-utils.h

@@ -33,9 +33,6 @@ G_BEGIN_DECLS
  */
 #define gcal_clear_date_time(dt) g_clear_pointer (dt, g_date_time_unref)
 
-gboolean             gcal_set_date_time                          (GDateTime         **dest,
-                                                                  GDateTime          *src);
-
 guint8               gcal_date_time_get_days_in_month            (GDateTime          *date);
 
 GDateTime*           gcal_date_time_get_start_of_week            (GDateTime          *date);