Link error when building Android plugin

[Ole Bromose]

Hi,

I'm writing a plugin named GstUsbSink with GstAudioSink as base class. 
In the beginning of gstusbsink.c I have the following lines, which 
should be standard for a GObject class definition:

...
static void gst_usbsink_init_interfaces (GType type);
#define gst_usbsink_parent_class parent_class
G_DEFINE_TYPE (GstUsbSink, gst_usbsink, GST_TYPE_AUDIO_SINK);   // <---- 
line 112
...

However, line 112 results in the following error:

./obj/local/armeabi/objs/dstreamer/gstusbsink.o: in function 
gst_usbsink_get_type:jni/gstusbsink.c:112: error: undefined reference to 
'gst_audio_sink_get_type'

I'm building the plugin together with the app.
I suppose that gst_audio_sink_get_type is defined by the base class 
(GstAudioSink). Thus, it looks like GstAudioSink is not included in the 
plugins. The included plugins are:

GSTREAMER_PLUGINS         := $(GSTREAMER_PLUGINS_CORE) 
$(GSTREAMER_PLUGINS_PLAYBACK) $(GSTREAMER_PLUGINS_CODECS) 
$(GSTREAMER_PLUGINS_NET) $(GSTREAMER_PLUGINS_SYS) 
$(GSTREAMER_PLUGINS_CODECS_RESTRICTED)

Is it correct that GstAudioSink is missing? Ifso, how do I get it included?

Best regards
Ole