gst: Add a gst_is_initialized() API

For one, this will allow libraries that expect applications to
initialize GStreamer before using their API to have a check for this
condition.

https://bugzilla.gnome.org/show_bug.cgi?id=627438

docs/gst/gstreamer-sections.txt

@@ -22,6 +22,7 @@
 gst_init
 gst_init_check
 gst_init_get_option_group
+gst_is_initialized
 gst_deinit
 gst_version
 gst_version_string

gst/gst.c

@@ -500,6 +500,22 @@ gst_init (int *argc, char **argv[])
   }
 }
 
+/**
+ * gst_is_initialized:
+ *
+ * Use this function to check if GStreamer has been initialized with gst_init()
+ * or gst_init_check().
+ *
+ * Returns: TRUE if initialization has been done, FALSE otherwise.
+ *
+ * Since: 0.10.31
+ */
+gboolean
+gst_is_initialized (void)
+{
+  return gst_initialized;
+}
+
 #ifndef GST_DISABLE_REGISTRY
 static void
 add_path_func (gpointer data, gpointer user_data)

gst/gst.h

@@ -85,6 +85,7 @@ G_BEGIN_DECLS
 void		gst_init			(int *argc, char **argv[]);
 gboolean	gst_init_check			(int *argc, char **argv[],
 						 GError ** err);
+gboolean        gst_is_initialized              (void);
 GOptionGroup *	gst_init_get_option_group	(void);
 void		gst_deinit			(void);
 

win32/common/libgstreamer.def

@@ -465,6 +465,7 @@ EXPORTS
 	gst_init_check
 	gst_init_get_option_group
 	gst_int_range_get_type
+	gst_is_initialized
 	gst_is_tag_list
 	gst_iterator_filter
 	gst_iterator_find_custom