mme: Add GTPv2 support

this includes a GTPv2_CodecPort (for the usual transcoding)
as wella as an empty GTPv2_PrivateExtensions.ttcn without which
the TITAN GTPv2 ProtocolModule won't compile.

Change-Id: I1c1b8409077103dd4e64e467d21d33d8c9c4ac95
diff --git a/library/GTPv2_PrivateExtensions.ttcn b/library/GTPv2_PrivateExtensions.ttcn
new file mode 100644
index 0000000..63552f2
--- /dev/null
+++ b/library/GTPv2_PrivateExtensions.ttcn
@@ -0,0 +1,21 @@
+module GTPv2_PrivateExtensions {
+
+/* This is a small stub module to make GTPv2_Types.ttcn from
+ * titan.ProtocolModules.GTPv2_v13.7.0 compile */
+
+import from General_Types all;
+
+type record PrivateExtension {
+	OCT1		elementIdentifier,
+	LIN2_BO_LAST	lengthIndicator,
+	BIT4		instance,
+	BIT4		spare,
+	octetstring	data
+} with {
+	variant (lengthIndicator) "LENGTHTO(data)";
+	variant "PRESENCE (elementIdentifier = 'FE'O; )"
+}
+
+type record of PrivateExtension PrivateExtension_List;
+
+} with{ encode "RAW" }