bsc: Start creating 08.08 like API

The 08.08 API will interface with the internal BSC code and it is
the boundary between MSC and BSC. So nothing that calls the BSC
functionality should know about lchan or such.
diff --git a/openbsc/include/openbsc/Makefile.am b/openbsc/include/openbsc/Makefile.am
index 483997a..6a87782 100644
--- a/openbsc/include/openbsc/Makefile.am
+++ b/openbsc/include/openbsc/Makefile.am
@@ -7,5 +7,5 @@
 		 silent_call.h mgcp.h meas_rep.h rest_octets.h \
 		 system_information.h handover.h mgcp_internal.h
 
-openbsc_HEADERS = gsm_04_08.h meas_rep.h
+openbsc_HEADERS = gsm_04_08.h meas_rep.h bsc_api.h
 openbscdir = $(includedir)/openbsc
diff --git a/openbsc/include/openbsc/bsc_api.h b/openbsc/include/openbsc/bsc_api.h
new file mode 100644
index 0000000..51e344f
--- /dev/null
+++ b/openbsc/include/openbsc/bsc_api.h
@@ -0,0 +1,6 @@
+/* GSM 08.08 like API for OpenBSC */
+
+#include "gsm_data.h"
+
+
+int gsm0808_submit_dtap(struct gsm_subscriber_connection *conn, struct msgb *msg, int link_id);