script: Hide private symbols

A bunch of private functions we use when parsing got exposed accidentaly
to the list of public symbols by virtue of not having the leading '_'
that we use to filter them out of the shared object — all the while the
header that declares them is a private, non installed one.

Let's rectify this situation with a bit of minor surgery on the code.

clutter/clutter-animation.c

@@ -431,7 +431,7 @@ clutter_animation_parse_custom_node (ClutterScriptable *scriptable,
     {
       gulong mode;
 
-      mode = clutter_script_resolve_animation_mode (node);
+      mode = _clutter_script_resolve_animation_mode (node);
 
       g_value_init (value, G_TYPE_ULONG);
       g_value_set_ulong (value, mode);