docs: add aggregator _get_type functions for signals + properties

https://bugzilla.gnome.org/show_bug.cgi?id=775379
diff --git a/docs/libs/Makefile.am b/docs/libs/Makefile.am
index 7919d66..f294bd0 100644
--- a/docs/libs/Makefile.am
+++ b/docs/libs/Makefile.am
@@ -57,6 +57,9 @@
 # contains GtkObjects/GObjects and you want to document signals and properties.
 GTKDOC_CFLAGS = -DGST_USE_UNSTABLE_API $(GST_PLUGINS_BAD_CFLAGS) $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS)
 GTKDOC_LIBS = \
+	$(top_builddir)/gst-libs/gst/base/libgstbadbase-@GST_API_VERSION@.la \
+	$(top_builddir)/gst-libs/gst/audio/libgstbadaudio-@GST_API_VERSION@.la \
+	$(top_builddir)/gst-libs/gst/video/libgstbadvideo-@GST_API_VERSION@.la \
 	$(top_builddir)/gst-libs/gst/codecparsers/libgstcodecparsers-@GST_API_VERSION@.la \
 	$(top_builddir)/gst-libs/gst/gl/libgstgl-@GST_API_VERSION@.la \
 	$(top_builddir)/gst-libs/gst/insertbin/libgstinsertbin-@GST_API_VERSION@.la \