[sccp] Implement parts of ITU SCCP for use in the A-Interface

include/sccp/sccp_types.h contain Q.713 and GSM definitions
include/sccp/sccp.h is the application interface resembling
                    the esentials of the UNIX socket interface.

src/sccp.c is the actual implementation of SCCP featuring
           connection and UDT1 support.

tests/sccp/sccp.c is testing connection creation and formating
                  of the SCCP messages used by the A-interface. And
                  it contains a simple fuzzing test to test the
                  robustnes of the implementation.
diff --git a/openbsc/configure.in b/openbsc/configure.in
index 25c5029..cba6c6c 100644
--- a/openbsc/configure.in
+++ b/openbsc/configure.in
@@ -40,6 +40,7 @@
     openbsc.pc
     include/openbsc/Makefile
     include/vty/Makefile
+    include/sccp/Makefile
     include/Makefile
     src/Makefile
     tests/Makefile
@@ -49,4 +50,5 @@
     tests/gsm0408/Makefile
     tests/db/Makefile
     tests/channel/Makefile
+    tests/sccp/Makefile
     Makefile)