In preparation for the potential Taproot soft fork, libconsensus should be updated to support verifying Taproot scripts.

There are two changes I see as necessary:

- Add a VERIFY_TAPROOT flag
- Change the API to support passing in spent outputs (bitcoinconsensus_verify_script_with_spent_outputs?)
IFY | bitcoinconsensus_SCRIPT_FLAGS_VERIFY_WITNESS
};
EXPORT_SYMBOL int bitcoinconsensus_verify_script(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen,
                                                 const unsigned char *txTo        , unsigned int txToLen,
                                                 unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err);
EXPORT_SYMBOL int bitcoinconsensus_verify_script_with_amount(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen, int64_t amount,
                                    const unsigned char *txTo        , unsigned int txToLen,
                                    unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err);
EXPORT_SYMBOL unsigned int bitcoinconsensus_version();
#ifdef __cplusplus
} 
#endif
#undef EXPORT_SYMBOL
#endif 
