diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am
index f012003..c8e3696 100644
--- a/openbsc/src/gprs/Makefile.am
+++ b/openbsc/src/gprs/Makefile.am
@@ -27,7 +27,8 @@
 			gprs_llc.c gprs_llc_parse.c gprs_llc_vty.c crc24.c \
 			sgsn_ctrl.c sgsn_auth.c gprs_subscriber.c \
 			gprs_gsup_messages.c gprs_utils.c gprs_gsup_client.c \
-			gsm_04_08_gprs.c sgsn_cdr.c sgsn_ares.c
+			gsm_04_08_gprs.c sgsn_cdr.c sgsn_ares.c \
+			oap.c oap_messages.c
 osmo_sgsn_LDADD = 	\
 			$(top_builddir)/src/libcommon/libcommon.a \
 			-lgtp $(OSMO_LIBS) $(LIBOSMOABIS_LIBS) $(LIBCARES_LIBS) \