Turn libosmo-mgcp into local, non-installed library

This is an internal library simmilar to 'libmsc' in osmo-msc, which
we don't expect to be used by other programs except osmo-mgw.  Hence,
there's no need to install it as a shared library, which introduces
requirements about ABI/API stability and the like.

osmo-bsc_nat uses libosmo-legacy-mgcp, and once we should rewrite
osmo-bsc_nat, we might need some of the libosmo-mgcp related functions,
but at this point it's unclear what exactly would be needed and if
current libosmo-mgcp can provide that.  As needed, we can introduce
a related shared library at that point.

Change-Id: Iba0a2c9c694e360356ac2ca584e97795281c6198
diff --git a/src/libosmo-mgcp/Makefile.am b/src/libosmo-mgcp/Makefile.am
index fbb1a2e..a98c391 100644
--- a/src/libosmo-mgcp/Makefile.am
+++ b/src/libosmo-mgcp/Makefile.am
@@ -21,19 +21,15 @@
 	$(COVERAGE_LDFLAGS) \
 	$(NULL)
 
-# This is not at all related to the release version, but a range of supported
-# API versions. Read TODO_RELEASE in the source tree's root!
-MGCP_LIBVERSION=1:0:0
-
-lib_LTLIBRARIES = \
-	libosmo-mgcp.la \
+noinst_LIBRARIES = \
+	libosmo-mgcp.a \
 	$(NULL)
 
 noinst_HEADERS = \
 	g711common.h \
 	$(NULL)
 
-libosmo_mgcp_la_SOURCES = \
+libosmo_mgcp_a_SOURCES = \
 	mgcp_protocol.c \
 	mgcp_network.c \
 	mgcp_vty.c \
@@ -44,5 +40,3 @@
 	mgcp_stat.c \
 	mgcp_endp.c \
 	$(NULL)
-
-libosmo_mgcp_la_LDFLAGS = $(AM_LDFLAGS) -version-info $(MGCP_LIBVERSION)