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-animation.c

@@ -1837,8 +1837,16 @@ clutter_animation_setup_valist (ClutterAnimation *animation,
               break;
             }
 
+#if GLIB_CHECK_VERSION (2, 23, 2)
+          G_VALUE_COLLECT_INIT (&file, G_PARAM_SPEC_VALUE_TYPE (pspec),
+                                var_args, 0,
+                                &error);
+#else
+          /* this is the same as G_VALUE_COLLECT_INIT(), but slower */
           g_value_init (&final, G_PARAM_SPEC_VALUE_TYPE (pspec));
           G_VALUE_COLLECT (&final, var_args, 0, &error);
+#endif /* GLIB_CHECK_VERSION (2, 23, 2) */
+
           if (error)
             {
               g_warning ("%s: %s", G_STRLOC, error);