diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am
index c044f24..3970ba6 100644
--- a/openbsc/src/gprs/Makefile.am
+++ b/openbsc/src/gprs/Makefile.am
@@ -93,6 +93,7 @@
 	oap.c \
 	oap_messages.c \
 	gprs_llc_xid.c \
+	v42bis.c \
 	$(NULL)
 osmo_sgsn_LDADD = \
 	$(top_builddir)/src/libcommon/libcommon.a \