re-structure the OpenBSC directory layout

The new structure divides the code into a number of libraries
for the BSC core functionality, MSC core functionality, Abis transport,
TRAU and other bits.

This doesn't introduce any functional code change but simply moves
around files and alters Makefile.am accordingly.

Next step would be to disentangle a lot of the inter-library
dependencies and make the individual bits of code more independent.
diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index 6507591..e4b2b96 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -2,51 +2,17 @@
 AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(COVERAGE_CFLAGS)
 AM_LDFLAGS = $(LIBOSMOCORE_LIBS) $(COVERAGE_LDFLAGS)
 
-# build current directory before building gprs
-SUBDIRS = . ipaccess gprs
+SUBDIRS = common abis mgcp bsc trau osmo-nitb utils ipaccess gprs
 
 # Conditional modules
 if BUILD_NAT
 SUBDIRS += nat
 endif
 if BUILD_BSC
-SUBDIRS += bsc
+SUBDIRS += osmo-bsc
 endif
 
-bin_PROGRAMS = bsc_hack bs11_config isdnsync bsc_mgcp
-noinst_LIBRARIES = libbsc.a libmsc.a libvty.a libmgcp.a
+bin_PROGRAMS = bsc_mgcp
 
-libbsc_a_SOURCES = abis_rsl.c abis_nm.c abis_om2000.c gsm_data.c gsm_04_08_utils.c \
-		chan_alloc.c debug.c socket.c abis_nm_vty.c abis_om2000_vty.c \
-		gsm_subscriber_base.c subchan_demux.c bsc_rll.c transaction.c \
-		trau_frame.c trau_mux.c paging.c \
-		e1_config.c e1_input.c e1_input_vty.c \
-		input/misdn.c input/ipaccess.c input/dahdi.c input/lapd.c \
-		handover_logic.c talloc_ctx.c system_information.c rest_octets.c \
-		bts_siemens_bs11.c bts_ipaccess_nanobts.c bts_ericsson_rbs2000.c mncc_upqueue.c \
-		bts_unknown.c bsc_version.c bsc_api.c bsc_vty.c meas_rep.c gsm_04_80.c
-
-libmsc_a_SOURCES = gsm_subscriber.c db.c \
-		mncc.c mncc_builtin.c mncc_sock.c \
-		gsm_04_08.c gsm_04_11.c transaction.c \
-		token_auth.c rrlp.c ussd.c silent_call.c \
-		handover_decision.c auth.c \
-		osmo_msc.c rtp_proxy.c
-
-libvty_a_SOURCES = common_vty.c
-
-libmgcp_a_SOURCES = mgcp/mgcp_protocol.c mgcp/mgcp_network.c mgcp/mgcp_vty.c
-
-bsc_hack_SOURCES = bsc_hack.c bsc_init.c bsc_vty.c vty_interface_layer3.c sms_queue.c
-bsc_hack_LDADD = libmsc.a libbsc.a libvty.a libmsc.a \
-		-ldl -ldbi $(LIBCRYPT) $(LIBOSMOVTY_LIBS)
-
-bs11_config_SOURCES = bs11_config.c abis_nm.c gsm_data.c debug.c \
-		      rs232.c bts_siemens_bs11.c
-
-isdnsync_SOURCES = isdnsync.c
-
-bsc_mgcp_SOURCES = mgcp/mgcp_main.c debug.c
-bsc_mgcp_LDADD = libvty.a libmgcp.a $(LIBOSMOVTY_LIBS)
-
-EXTRA_DIST = input/lapd.h
+bsc_mgcp_SOURCES = mgcp/mgcp_main.c
+bsc_mgcp_LDADD = common/libcommon.a mgcp/libmgcp.a $(LIBOSMOVTY_LIBS)