diff --git a/src/Makefile.am b/src/Makefile.am
index edac0c3..6f82a54 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,14 +5,30 @@ AM_CFLAGS=-Wall -g $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBOSMOVTY_CFLAG
 		   $(COVERAGE_CFLAGS)
 AM_LDFLAGS=$(COVERAGE_LDFLAGS)
 
-EXTRA_DIST = cbc_data.h cbsp_server.h charset.h internal.h rest_it_op.h
+EXTRA_DIST = \
+	cbc_data.h \
+	cbsp_server.h \
+	charset.h \
+	internal.h \
+	rest_it_op.h \
+	$(NULL)
 
 bin_PROGRAMS = osmo-cbc
 
-osmo_cbc_SOURCES = cbc_main.c cbc_data.c cbc_vty.c cbsp_server.c cbsp_server_fsm.c \
-		   rest_api.c charset.c message_handling.c rest_it_op.c \
-		   smscb_peer_fsm.c smscb_message_fsm.c
+osmo_cbc_SOURCES = \
+	cbc_main.c \
+	cbc_data.c \
+	cbc_vty.c \
+	cbsp_server.c \
+	cbsp_server_fsm.c \
+	rest_api.c \
+	charset.c \
+	message_handling.c \
+	rest_it_op.c \
+	smscb_peer_fsm.c \
+	smscb_message_fsm.c \
+	$(NULL)
+
 osmo_cbc_LDADD = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOVTY_LIBS) \
 		 $(LIBOSMONETIF_LIBS) \
 		 $(ULFIUS_LIBS) $(JANSSON_LIBS) $(ORCANIA_LIBS)
-