Fix linking with GNU ld 2.22 and libgps

Error:
gcc -Wall -I/home/kevredon/osmocom-bb/src/shared/libosmocore/include -I/home/kevredon/osmocom-bb/src/shared/libosmocore/include -g -O2 -D_HAVE_GPSD  -lgps -o cell_log main.o app_cell_log.o cell_log.o geo.o ../common/liblayer23.a /home/kevredon/osmocom-bb/src/shared/libosmocore/build-host/src/.libs/libosmocore.a /home/kevredon/osmocom-bb/src/shared/libosmocore/build-host/src/gsm/.libs/libosmogsm.a /home/kevredon/osmocom-bb/src/shared/libosmocore/build-host/src/codec/.libs/libosmocodec.a -lm
../common/liblayer23.a(gps.o): In function `osmo_gpsd_cb':
/home/kevredon/osmocom-bb/src/host/layer23/src/common/gps.c:79: undefined reference to `gps_waiting'

Fix:
Holger told me to do so (he knows better then me about autoconf)
- set CFLAGS and LIBS for LIBGPS in layer23
- add libgps CFLAGS and LIBS in Makefile.am for common, misc, mobile
I would have done the following (which also works):
-AC_CHECK_LIB(gps, gps_waiting, CFLAGS+=" -D_HAVE_GPSD" LDFLAGS+=" -lgps",,)
+AC_CHECK_LIB(gps, gps_waiting, CFLAGS+=" -D_HAVE_GPSD" LDFLAGS+=" -lgps" LIBS+=" -lgps",,)

4 files changed, 9 insertions, 6 deletions

diff --git a/src/host/layer23/configure.ac b/src/host/layer23/configure.ac
index b50868a5..9335e66e 100644
--- a/src/host/layer23/configure.ac
+++ b/src/host/layer23/configure.ac
@@ -17,7 +17,10 @@ PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore)
 PKG_CHECK_MODULES(LIBOSMOVTY, libosmovty)
 PKG_CHECK_MODULES(LIBOSMOGSM, libosmogsm)
 PKG_CHECK_MODULES(LIBOSMOCODEC, libosmocodec)
-AC_CHECK_LIB(gps, gps_waiting, CFLAGS+=" -D_HAVE_GPSD" LDFLAGS+=" -lgps",,)
+AC_CHECK_LIB(gps, gps_waiting, LIBGPS_CFLAGS=" -D_HAVE_GPSD" LIBGPS_LIBS=" -lgps ",,)
+AC_SUBST([LIBGPS_CFLAGS])
+AC_SUBST([LIBGPS_LIBS])
+
 
 dnl checks for header files
 AC_HEADER_STDC
diff --git a/src/host/layer23/src/common/Makefile.am b/src/host/layer23/src/common/Makefile.am
index 73a0fc96..8d96ed2c 100644
--- a/src/host/layer23/src/common/Makefile.am
+++ b/src/host/layer23/src/common/Makefile.am
@@ -1,5 +1,5 @@
 INCLUDES = $(all_includes) -I$(top_srcdir)/include
-AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS)
+AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBGPS_CFLAGS)
 
 noinst_LIBRARIES = liblayer23.a
 liblayer23_a_SOURCES = l1ctl.c l1l2_interface.c sap_interface.c \
diff --git a/src/host/layer23/src/misc/Makefile.am b/src/host/layer23/src/misc/Makefile.am
index 0b59f389..d8fb3222 100644
--- a/src/host/layer23/src/misc/Makefile.am
+++ b/src/host/layer23/src/misc/Makefile.am
@@ -1,6 +1,6 @@
 INCLUDES = $(all_includes) -I$(top_srcdir)/include
-AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS)
-LDADD = ../common/liblayer23.a $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOCODEC_LIBS)
+AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBGPS_CFLAGS)
+LDADD = ../common/liblayer23.a $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOCODEC_LIBS) $(LIBGPS_LIBS)
 
 bin_PROGRAMS = bcch_scan ccch_scan echo_test cell_log cbch_sniff
 
diff --git a/src/host/layer23/src/mobile/Makefile.am b/src/host/layer23/src/mobile/Makefile.am
index f3365af5..8920c54a 100644
--- a/src/host/layer23/src/mobile/Makefile.am
+++ b/src/host/layer23/src/mobile/Makefile.am
@@ -1,6 +1,6 @@
 INCLUDES = $(all_includes) -I$(top_srcdir)/include
-AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS)
-LDADD = ../common/liblayer23.a $(LIBOSMOCORE_LIBS) $(LIBOSMOVTY_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOCODEC_LIBS)
+AM_CFLAGS = -Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGSM_CFLAGS) $(LIBGPS_CFLAGS)
+LDADD = ../common/liblayer23.a $(LIBOSMOCORE_LIBS) $(LIBOSMOVTY_LIBS) $(LIBOSMOGSM_LIBS) $(LIBOSMOCODEC_LIBS) $(LIBGPS_LIBS)
 
 noinst_LIBRARIES = libmobile.a
 libmobile_a_SOURCES = gsm322.c gsm480_ss.c gsm411_sms.c gsm48_cc.c gsm48_mm.c \