API: add GST_QUERY_CAST

because we can, and for consistency.

docs/gst/gstreamer-sections.txt

@@ -1818,6 +1818,7 @@ gst_query_set_uri
 <SUBSECTION Standard>
 GstQueryClass
 GST_QUERY
+GST_QUERY_CAST
 GST_IS_QUERY
 GST_QUERY_CLASS
 GST_IS_QUERY_CLASS

gst/gstquery.h

@@ -114,8 +114,10 @@ struct _GstQueryTypeDefinition
 #define GST_IS_QUERY_CLASS(klass)              (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_QUERY))
 #define GST_QUERY_GET_CLASS(obj)               (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_QUERY, GstQueryClass))
 #define GST_QUERY(obj)                         (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_QUERY, GstQuery))
+#define GST_QUERY_CAST(obj)                    ((GstQuery*)(obj)) /* only since 0.10.23 */
 #define GST_QUERY_CLASS(klass)                 (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_QUERY, GstQueryClass))
 
+
 /**
  * GST_QUERY_TYPE:
  * @query: the query to query