Conditionally use G_VALUE_COLLECT_INIT() macro

GLib 2.24 (but starting from the 2.23.2 unstable release) added a new
macro for collecting GValues from a va_list.

The newly added G_VALUE_COLLECT_INIT() macro should be used in place
of initializing the GValue and calling G_VALUE_COLLECT(), and improves
the collection performances by avoiding multiple checks, free and
initialization calls.

clutter/clutter-container.c

@@ -1019,8 +1019,15 @@ clutter_container_child_set (ClutterContainer *container,
           break;
         }
 
+#if GLIB_CHECK_VERSION (2, 23, 2)
+      G_VALUE_COLLECT_INIT (&value, G_PARAM_SPEC_VALUE_TYPE (pspec),
+                            var_args, 0,
+                            &error);
+#else
       g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (pspec));
       G_VALUE_COLLECT (&value, var_args, 0, &error);
+#endif /* GLIB_CHECK_VERSION (2, 23, 2) */
+
       if (error)
         {
           /* we intentionally leak the GValue because it might