Add ipaccess-proxy, a proxy for ip.access A-bis over IP

This proxy allows us to restart OpenBSC while the BTS's are kept
running with their CCCH/BCCH alive.  This is very useful to
make sure the phones don't roam to other networks while restarting
OpenBSC.

The proxy also intrduces UDP sockets for injecting UDP packets
into the A-bis data stream.

openbsc/src/Makefile.am

@@ -2,7 +2,7 @@ INCLUDES = $(all_includes) -I$(top_srcdir)/include
 AM_CFLAGS=-Wall
 
 sbin_PROGRAMS = bsc_hack bs11_config ipaccess-find ipaccess-config \
-                isdnsync bsc_mgcp ipaccess_firmware
+                isdnsync bsc_mgcp ipaccess_firmware ipaccess-proxy
 noinst_LIBRARIES = libbsc.a libmsc.a libvty.a libsccp.a
 noinst_HEADERS = vty/cardshell.h
 
@@ -40,3 +40,5 @@ bsc_mgcp_SOURCES = bsc_mgcp.c msgb.c talloc.c debug.c select.c timer.c telnet_in
 bsc_mgcp_LDADD = libvty.a
 
 ipaccess_firmware_SOURCES = ipaccess-firmware/ipaccess-firmware.c
+
+ipaccess_proxy_SOURCES = ipaccess-proxy.c msgb.c select.c talloc.c debug.c timer.c