aggregator: fix exports and since marker for new API

https://bugzilla.gnome.org/show_bug.cgi?id=795332
diff --git a/libs/gst/base/gstaggregator.c b/libs/gst/base/gstaggregator.c
index b67f36d..b72b013 100644
--- a/libs/gst/base/gstaggregator.c
+++ b/libs/gst/base/gstaggregator.c
@@ -2951,7 +2951,7 @@
  *
  * Returns: %TRUE if the pad has a buffer available as the next thing.
  *
- * Since: 1.16
+ * Since: 1.14.1
  */
 gboolean
 gst_aggregator_pad_has_buffer (GstAggregatorPad * pad)
diff --git a/win32/common/libgstbase.def b/win32/common/libgstbase.def
index 528ed98..792a86d 100644
--- a/win32/common/libgstbase.def
+++ b/win32/common/libgstbase.def
@@ -37,6 +37,7 @@
 	gst_aggregator_get_type
 	gst_aggregator_pad_drop_buffer
 	gst_aggregator_pad_get_type
+	gst_aggregator_pad_has_buffer
 	gst_aggregator_pad_is_eos
 	gst_aggregator_pad_peek_buffer
 	gst_aggregator_pad_pop_buffer