Build fails on FreeBSD 12.1 #17973

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After following instructions on https://github.com/bitcoin/bitcoin/blob/master/doc/build-freebsd.md (with the additions of installing packages libzmq4 and openssl) in a newly created jail it fails with the error:

CXX wallet/libbitcoin_wallet_a-walletutil.o wallet/walletutil.cpp:77:23: error: no member named 'level' in 'boost::filesystem::recursive_directory_iterator' } else if (it.level() == 0 && it->symlink_status().type() == fs::regular_file && IsBerkeleyBtree(it->path())) {

System information Newly created 12.1 jail

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checked out tag v0.19.0.1

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Seems to be related to deprecation of level() member of recursive_directory_iterator of the boost library. https://www.boost.org/users/history/version_1_72_0.html

This seems to be (sort of) a duplicate of #17856 and will probably be fixed due to #17654