Pick up Stellar-internal.x (#4)

Stellar-internal.x

@@ -0,0 +1,32 @@
+// Copyright 2022 Stellar Development Foundation and contributors. Licensed
+// under the Apache License, Version 2.0. See the COPYING file at the root
+// of this distribution or at http://www.apache.org/licenses/LICENSE-2.0
+
+// This is for 'internal'-only messages that are not meant to be read/written
+// by any other binaries besides a single Core instance.
+%#include "xdr/Stellar-ledger.h"
+%#include "xdr/Stellar-SCP.h"
+
+namespace stellar
+{
+union StoredTransactionSet switch (int v)
+{
+case 0:
+	TransactionSet txSet;
+case 1:
+	GeneralizedTransactionSet generalizedTxSet;
+};
+
+struct PersistedSCPStateV0
+{
+	SCPEnvelope scpEnvelopes<>;
+	SCPQuorumSet quorumSets<>;
+	StoredTransactionSet txSets<>;
+};
+
+union PersistedSCPState switch (int v)
+{
+case 0:
+	PersistedSCPStateV0 v0;
+};
+}