build: add libupf.la (noinst)

Like we do in osmo-bsc.git, gather the osmo-upf objects into a
not-installed libupf.la, so that we can trivially and flexibly link
these to regression test programs.

Will be used by upcoming patch I36acff15f22d23ade4d281c2af3eb117dfc10359
(unique_ids_test).

Change-Id: Id179a47b5d40821d86c7214add14449600198e07

src/osmo-upf/Makefile.am

@@ -18,19 +18,15 @@ AM_CFLAGS = \
 	$(NULL)
 
 AM_LDFLAGS = \
-	$(LIBGTPNL_LDFLAGS) \
-	$(LIBNFTNL_LDFLAGS) \
-	$(LIBNFTABLES_LDFLAGS) \
 	$(COVERAGE_LDFLAGS) \
 	$(NULL)
 
-bin_PROGRAMS = \
-	osmo-upf \
+noinst_LTLIBRARIES = \
+	libupf.la \
 	$(NULL)
 
-osmo_upf_SOURCES = \
+libupf_la_SOURCES = \
 	netinst.c \
-	osmo_upf_main.c \
 	up_endpoint.c \
 	up_gtp_action.c \
 	up_peer.c \
@@ -42,7 +38,7 @@ osmo_upf_SOURCES = \
 	upf_vty.c \
 	$(NULL)
 
-osmo_upf_LDADD = \
+libupf_la_LIBADD = \
 	$(LIBOSMOCORE_LIBS) \
 	$(LIBOSMOVTY_LIBS) \
 	$(LIBOSMOCTRL_LIBS) \
@@ -50,5 +46,16 @@ osmo_upf_LDADD = \
 	$(LIBGTPNL_LIBS) \
 	$(LIBNFTNL_LIBS) \
 	$(LIBNFTABLES_LIBS) \
-	$(COVERAGE_LDFLAGS) \
+	$(NULL)
+
+bin_PROGRAMS = \
+	osmo-upf \
+	$(NULL)
+
+osmo_upf_SOURCES = \
+	osmo_upf_main.c \
+	$(NULL)
+
+osmo_upf_LDADD = \
+	libupf.la \
 	$(NULL)