Does not compile on Ubuntu 20.04.
Try add ntp.h and ntp.cpp to ..\src\makefile.am
That did not help.
/usr/include/boost/asio/ssl/impl/context.ipp:63:1: note: candidate expects 1 argument, 2 provided
CC libbitcoin_server_a-keccak.o
bitcoinrpc.cpp: In instantiation of \u2018void RPCListen(boost::shared_ptr<boost::asio::basic_socket_acceptor<Protocol, SocketAcceptorService> >, boost::asio::ssl::context&, bool) [with Protocol = boost::asio::ip::tcp; SocketAcceptorService = boost::asio::executor]\u2019:
bitcoinrpc.cpp:836:45: required from here
bitcoinrpc.cpp:703:93: error: \u2018class boost::asio::basic_socket_acceptor<boost::asio::ip::tcp>\u2019 has no member named \u2018get_io_service\u2019
703 | AcceptedConnectionImpl<Protocol>* conn = new AcceptedConnectionImpl<Protocol>(acceptor->get_io_service(), context, fUseSSL);
| ~~~~~~~~~~^~~~~~~~~~~~~~
CXX libbitcoin_server_a-kernel.o
bitcoinrpc.cpp: In instantiation of \u2018bool SSLIOStreamDevice<Protocol>::connect(const string&, const string&) [with Protocol = boost::asio::ip::tcp; std::string = std::__cxx11::basic_string<char>]\u2019:
bitcoinrpc.cpp:1110:103: required from here
bitcoinrpc.cpp:597:43: error: \u2018class boost::asio::ssl::stream<boost::asio::basic_stream_socket<boost::asio::ip::tcp> >\u2019 has no member named \u2018get_io_service\u2019
597 | ip::tcp::resolver resolver(stream.get_io_service());
| ~~~~~~~^~~~~~~~~~~~~~
CC libbitcoin_server_a-luffa.o
CXX libbitcoin_server_a-main.o