diff --git a/gst-libs/gst/rtp/Makefile.am b/gst-libs/gst/rtp/Makefile.am
index 4c733f7717..613cc12fea 100644
--- a/gst-libs/gst/rtp/Makefile.am
+++ b/gst-libs/gst/rtp/Makefile.am
@@ -91,5 +91,5 @@ typelibs_DATA = $(BUILT_GIRSOURCES:.gir=.typelib)
 		--includedir=`PKG_CONFIG_PATH="$(GST_PKG_CONFIG_PATH)" $(PKG_CONFIG) --variable=girdir gstreamer-base-@GST_API_VERSION@` \
 		$(INTROSPECTION_COMPILER_OPTS) $< -o $(@F)
 
-CLEANFILES = $(BUILT_GIRSOURCES) $(typelibs_DATA)
+CLEANFILES += $(BUILT_GIRSOURCES) $(typelibs_DATA)
 endif