diff --git a/src/Makefile.am b/src/Makefile.am
index de161b1..7208674 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -11,10 +11,14 @@ INST_H_SRC_FILES = \
 INST_H_BUILT_FILES = \
 	gswe-enumtypes.h
 
-libswe_glib_sources = swe-glib.c gswe-moment.c gswe-timestamp.c gswe-enumtypes.c
 gswe_headers = gswe-timestamp.h gswe-types.h
 
-libswe_glib_1_0_la_SOURCES = $(libswe_glib_sources)
+libswe_glib_1_0_la_SOURCES = \
+	swe-glib.c       \
+	gswe-moment.c    \
+	gswe-timestamp.c \
+	gswe-enumtypes.c \
+	$(NULL)
 libswe_glib_1_0_la_CFLAGS = $(GLIB_CFLAGS) $(GOBJECT_CFLAGS) -Wall
 libswe_glib_1_0_la_LIBADD = $(GLIB_LIBS) $(GOBJECT_LIBS) $(LIBSWE_LIBS)