ges: Link ges plugin to libgstpbutils
/usr/bin/ld: .libs/libgstges_la-gesdemux.o: in function ges_timeline_new_from_uri_from_main_thread': ./plugins/ges/gesdemux.c:279: undefined reference to
gst_discoverer_new'
/usr/bin/ld: ./plugins/ges/gesdemux.c:288: undefined reference to `gst_discoverer_start'