gprs: Link gbproxy to -lrt for clock_gettime
On older GNU libc systems we need to link to this library to
use the clock_gettime symbol.
diff --git a/openbsc/src/gprs/Makefile.am b/openbsc/src/gprs/Makefile.am
index a8de0a4..3957877 100644
--- a/openbsc/src/gprs/Makefile.am
+++ b/openbsc/src/gprs/Makefile.am
@@ -17,7 +17,7 @@
gb_proxy_patch.c gb_proxy_tlli.c gb_proxy_peer.c \
gprs_gb_parse.c gprs_llc_parse.c crc24.c gprs_utils.c
osmo_gbproxy_LDADD = $(top_builddir)/src/libcommon/libcommon.a \
- $(OSMO_LIBS)
+ $(OSMO_LIBS) -lrt
osmo_sgsn_SOURCES = gprs_gmm.c gprs_sgsn.c gprs_sndcp.c gprs_sndcp_vty.c \
sgsn_main.c sgsn_vty.c sgsn_libgtp.c \