On fresh Ubuntu 20.04, with dependencies installed via apt:
0$ ./configure CC=gcc-10 CXX=g++-10
1$ make -C src test/test_bitcoin
2make: Entering directory '/bitcoin/src'
3 CXX test/test_bitcoin-main.o
4In file included from /usr/include/boost/test/included/unit_test.hpp:29,
5 from test/main.cpp:10:
6/usr/include/boost/test/impl/test_tools.ipp: In member function 'void boost::test_tools::tt_detail::print_log_value<const wchar_t*>::operator()(std::ostream&, const wchar_t*)':
7/usr/include/boost/test/impl/test_tools.ipp:127:38: error: use of deleted function 'std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const wchar_t*) [with _Traits = std::char_traits<char>]'
8 127 | ostr << ( t ? t : L"null string" );
9 | ^
10In file included from /usr/include/c++/10/iostream:39,
11 from /usr/include/boost/test/unit_test_log_formatter.hpp:26,
12 from /usr/include/boost/test/output/compiler_log_formatter.hpp:17,
13 from /usr/include/boost/test/impl/compiler_log_formatter.ipp:19,
14 from /usr/include/boost/test/included/unit_test.hpp:18,
15 from test/main.cpp:10:
16/usr/include/c++/10/ostream:634:5: note: declared here
17 634 | operator<<(basic_ostream<char, _Traits>&, const wchar_t*) = delete;
18 | ^~~~~~~~
19make: *** [Makefile:18328: test/test_bitcoin-main.o] Error 1
20make: Leaving directory '/bitcoin/src'
