separate libosmo-mgcp-client from mgcp server code

When osmo-mgw is built --with-mgcp-transcoding, linking the mgcp library
also requires linking libgsm, even though e.g. osmo-msc never use it.
Separate the MGCP client code from the MGCP server code to avoid this dep.

The mgcp client code does use some definitions from mgcp.h and mgcp_common.c.
For simplicity, link mgcp_common.c in both libosmo-legacy-mgcp as well as
libosmo-mgcp-client. That means it is not possible to link both
libosmo-legacy-mgcp and libosmo-mgcp-client in the same binary because of
duplicate symbols, but currently that is sufficient. (An alternative would be
code dup or yet another libosmo-mgcp-common library.)

Add libosmo-mgcp-client to debian packaging.

Related: OS#2488
Change-Id: I8e0b2d2a399b77086a36606f5e427271c6242df1
diff --git a/tests/mgcp_client/Makefile.am b/tests/mgcp_client/Makefile.am
new file mode 100644
index 0000000..2253770
--- /dev/null
+++ b/tests/mgcp_client/Makefile.am
@@ -0,0 +1,38 @@
+AM_CPPFLAGS = \
+	$(all_includes) \
+	-I$(top_srcdir)/include \
+	-I$(top_srcdir) \
+	$(NULL)
+
+AM_CFLAGS = \
+	-Wall \
+	-ggdb3 \
+	$(LIBOSMOCORE_CFLAGS) \
+	$(LIBOSMONETIF_CFLAGS) \
+	$(COVERAGE_CFLAGS) \
+	$(NULL)
+
+AM_LDFLAGS = \
+	$(COVERAGE_LDFLAGS) \
+	$(NULL)
+
+EXTRA_DIST = \
+	mgcpgw_client_test.ok \
+	mgcpgw_client_test.err \
+	$(NULL)
+
+noinst_PROGRAMS = \
+	mgcpgw_client_test \
+	$(NULL)
+
+mgcpgw_client_test_SOURCES = \
+	mgcpgw_client_test.c \
+	$(NULL)
+
+mgcpgw_client_test_LDADD = \
+	$(top_builddir)/src/libosmo-mgcp-client/libosmo-mgcp-client.la \
+	$(LIBOSMOCORE_LIBS) \
+	$(LIBOSMOVTY_LIBS) \
+	$(LIBRARY_DL) \
+	$(LIBOSMONETIF_LIBS) \
+	$(NULL)