diff --git a/openbsc/src/libfilter/Makefile.am b/openbsc/src/libfilter/Makefile.am
index e24ec5f..d79afb2 100644
--- a/openbsc/src/libfilter/Makefile.am
+++ b/openbsc/src/libfilter/Makefile.am
@@ -5,5 +5,6 @@
 noinst_LIBRARIES = libfilter.a
 
 libfilter_a_SOURCES = \
-	bsc_msg_filter.c
+	bsc_msg_filter.c \
+	bsc_msg_acc.c