gb: Add beginnings of a new BSSGP implementation

Similar to ns2 superseding ns, we now also intoduce a next generation
of BSSGP related code to libosmogb.  However, this is not aiming to
be a full implementation yet, but simply those parts that we currently
need from the revamped osmo-gbproxy.

The gprs_bssgp2.[ch] differs in two ways from the old code:
* it separates message encoding from message transmission
* it supports more recent specs / IEs

bssgp_bvc_fsm.c is a genric implementation of the BSSGP BVC
RESET/BLOCK/UNBLOCK logic with support for both PTP and signaling,
both on the SGSN side and the BSS side.

Change-Id: Icbe8e4f03b68fd73b8eae95f6f6cccd4fa9af95a
diff --git a/include/Makefile.am b/include/Makefile.am
index f67e1ad..0cb9cd2 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -64,7 +64,9 @@
 		       osmocom/ctrl/control_if.h \
 		       osmocom/ctrl/ports.h \
                        osmocom/gprs/frame_relay.h \
+                       osmocom/gprs/bssgp_bvc_fsm.h \
                        osmocom/gprs/gprs_bssgp.h \
+                       osmocom/gprs/gprs_bssgp2.h \
                        osmocom/gprs/gprs_bssgp_bss.h \
                        osmocom/gprs/gprs_msgb.h \
                        osmocom/gprs/gprs_ns.h \