remove unused-variable compile flag
remove unused-variable compile flag

macos CI fails due to eth cpp stuff


Former-commit-id: 3c1e3132051c15efdec23b62786bd09d6dedeb6d
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin