message: Add future declaration of GetWitnessCommitmentIndex
diff: @@ -237,6 +237,7 @@ enum FlushStateMode {
  // See definition for documentation
  bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode, int nManualPruneHeight=0);
  void FindFilesToPruneManual(std::set<int>& setFilesToPrune, int nManualPruneHeight);
  +static int GetWitnessCommitmentIndex(const CBlock& block);
  bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime)
  {
  