[Version3] unused function warnings.

[evoskuil]

These local static functions are all invoked by exported functions in the same .cpp file and there is no signature ambuguity.

CXX      src/wallet/src_libbitcoin_la-hd_private.lo
src/wallet/encrypted_keys.cpp:74:13: warning: ‘bool libbitcoin::wallet::address_salt(libbitcoin::wallet::ek_salt&, const ec_secret&, uint8_t, bool)’ defined but not used [-Wunused-function]
 static bool address_salt(ek_salt& salt, const ec_secret& secret,
             ^
src/wallet/encrypted_keys.cpp:88:13: warning: ‘bool libbitcoin::wallet::address_validate(const ek_salt&, const ec_compressed&, uint8_t, bool)’ defined but not used [-Wunused-function]
 static bool address_validate(const ek_salt& salt, const ec_compressed& point,
             ^
src/wallet/encrypted_keys.cpp:95:13: warning: ‘bool libbitcoin::wallet::address_validate(const ek_salt&, const ec_secret&, uint8_t, bool)’ defined but not used [-Wunused-function]
 static bool address_validate(const ek_salt& salt, const ec_secret& secret,
             ^
src/wallet/encrypted_keys.cpp:119:17: warning: ‘libbitcoin::one_byte libbitcoin::wallet::point_sign(const one_byte&, const hash_digest&)’ defined but not used [-Wunused-function]
 static one_byte point_sign(const one_byte& single, const hash_digest& hash)
                 ^
src/wallet/encrypted_keys.cpp:127:20: warning: ‘libbitcoin::hash_digest libbitcoin::wallet::scrypt_token(libbitcoin::data_slice, libbitcoin::data_slice)’ defined but not used [-Wunused-function]
 static hash_digest scrypt_token(data_slice data, data_slice salt)
                    ^
src/wallet/encrypted_keys.cpp:139:18: warning: ‘libbitcoin::long_hash libbitcoin::wallet::scrypt_private(libbitcoin::data_slice, libbitcoin::data_slice)’ defined but not used [-Wunused-function]
 static long_hash scrypt_private(data_slice data, data_slice salt)
                  ^
src/wallet/encrypted_keys.cpp:169:17: warning: ‘libbitcoin::one_byte libbitcoin::wallet::set_flags(bool)’ defined but not used [-Wunused-function]
 static one_byte set_flags(bool compressed)
                 ^

https://travis-ci.org/github/libbitcoin/libbitcoin-system/jobs/763760390#L1014-L1035

[evoskuil]

gcc 4.8 is dated March 22, 2013... we can probably move on.

[evoskuil]

Also from:

$ clang --version
Apple LLVM version 9.1.0 (clang-902.0.39.2)
Target: x86_64-apple-darwin17.7.0
Thread model: posix

[evoskuil]

Legit issue, these functions are only invoked in WITH_ICU builds. The issue was previously resolved in master. Resolved in current version3 PR.