diff -r 9b2c3c7a1a9c -r 567bb019e3e3 gstreamer_core/gst/gstsystemclock.h
--- a/gstreamer_core/gst/gstsystemclock.h	Wed Mar 31 22:03:18 2010 +0300
+++ b/gstreamer_core/gst/gstsystemclock.h	Tue Aug 31 15:30:33 2010 +0300
@@ -31,6 +31,7 @@
 
 #define GST_TYPE_SYSTEM_CLOCK 			(gst_system_clock_get_type ())
 #define GST_SYSTEM_CLOCK(obj) 			(G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_SYSTEM_CLOCK, GstSystemClock))
+#define GST_SYSTEM_CLOCK_CAST(obj)		((GstSystemClock *)(obj))
 #define GST_IS_SYSTEM_CLOCK(obj) 		(G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_SYSTEM_CLOCK))
 #define GST_SYSTEM_CLOCK_CLASS(klass) 		(G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_SYSTEM_CLOCK, GstSystemClockClass))
 #define GST_IS_SYSTEM_CLOCK_CLASS(klass) 	(G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_SYSTEM_CLOCK))
@@ -39,6 +40,20 @@
 
 typedef struct _GstSystemClock GstSystemClock;
 typedef struct _GstSystemClockClass GstSystemClockClass;
+typedef struct _GstSystemClockPrivate GstSystemClockPrivate;
+
+/**
+ * GstClockType:
+ * @GST_CLOCK_TYPE_REALTIME: time since Epoch
+ * @GST_CLOCK_TYPE_MONOTONIC: monotonic time since some unspecified starting
+ *                            point
+ *
+ * The different kind of clocks.
+ */
+typedef enum {
+  GST_CLOCK_TYPE_REALTIME	= 0,
+  GST_CLOCK_TYPE_MONOTONIC	= 1
+} GstClockType;
 
 /**
  * GstSystemClock:
@@ -53,7 +68,10 @@
   GThread	*thread;	/* thread for async notify */
   gboolean 	 stopping;
 
-  gpointer _gst_reserved[GST_PADDING];
+  /* ABI added */
+  GstSystemClockPrivate *priv;
+
+  gpointer _gst_reserved[GST_PADDING - 1];
 };
 
 struct _GstSystemClockClass {