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-script.c

@@ -294,7 +294,7 @@ clutter_script_real_get_type_from_name (ClutterScript *script,
   if (gtype != G_TYPE_INVALID)
     return gtype;
 
-  return clutter_script_get_type_from_class (type_name);
+  return _clutter_script_get_type_from_class (type_name);
 }
 
 void