configure: Do not link all applications against libgsm
Use the same trick as done by the dlopen check to not
have everyone link against the library.
diff --git a/openbsc/src/osmo-bsc_mgcp/Makefile.am b/openbsc/src/osmo-bsc_mgcp/Makefile.am
index c62131b..949cb64 100644
--- a/openbsc/src/osmo-bsc_mgcp/Makefile.am
+++ b/openbsc/src/osmo-bsc_mgcp/Makefile.am
@@ -10,4 +10,5 @@
osmo_bsc_mgcp_LDADD = $(top_builddir)/src/libcommon/libcommon.a \
$(top_builddir)/src/libmgcp/libmgcp.a -lrt \
$(LIBOSMOVTY_LIBS) $(LIBOSMOCORE_LIBS) \
- $(LIBOSMONETIF_LIBS) $(LIBBCG729_LIBS)
+ $(LIBOSMONETIF_LIBS) $(LIBBCG729_LIBS) \
+ $(LIBRARY_GSM)