library: S1AP encoding/decoding using libfftranscode and ASN.1 from V15.5.0

This allows us to encode/decode 3GPP S1AP messages, as used on the S1
interface control plane between eNodeB and MME.

Change-Id: Ie019bef1f3ef9cc5f6c94a64c7f352c510fb5633
diff --git a/library/s1ap/S1AP_CommonDataTypes.asn b/library/s1ap/S1AP_CommonDataTypes.asn
new file mode 100644
index 0000000..20a9bb4
--- /dev/null
+++ b/library/s1ap/S1AP_CommonDataTypes.asn
@@ -0,0 +1,34 @@
+-- 3GPP TS 36.413 V15.5.0 (2019-03)
+-- 9.3.5	Common Definitions
+-- **************************************************************
+--
+-- Common definitions
+--
+-- **************************************************************
+
+S1AP-CommonDataTypes {
+itu-t (0) identified-organization (4) etsi (0) mobileDomain (0) 
+eps-Access (21) modules (3) s1ap (1) version1 (1) s1ap-CommonDataTypes (3) }
+
+DEFINITIONS AUTOMATIC TAGS ::= 
+
+BEGIN
+
+Criticality		::= ENUMERATED { reject, ignore, notify }
+
+Presence		::= ENUMERATED { optional, conditional, mandatory }
+
+PrivateIE-ID	::= CHOICE {
+	local				INTEGER (0..65535),
+	global				OBJECT IDENTIFIER
+}
+
+ProcedureCode		::= INTEGER (0..255)
+
+ProtocolExtensionID	::= INTEGER (0..65535)
+
+ProtocolIE-ID		::= INTEGER (0..65535)
+
+TriggeringMessage	::= ENUMERATED { initiating-message, successful-outcome, unsuccessfull-outcome }
+
+END