latest release doesn't compile with clang-8.0

Bug reports:

Please follow the general troubleshooting steps first:

• Are you running the latest graph-tool version?
• Do you observe the problem with the current git version?
• Are you using Macports or Homebrew? If yes, please submit an issue there instead: https://github.com/Homebrew/brew/issues and https://trac.macports.org/newticket
• Did you compile graph-tool manually?
• If you answered yes above, did you use the exact same compiler to build graph-tool, boost-python and Python?

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• A minimal and self-contained example that shows the problem.
• Your operating system.
• The Python version you are using.
• If you compiled graph-tool manually: Your compiler version, as well as the version of Boost being used.
• If you are reporting a compilation error, please provide the entire ./configure output, as well as the entire contents of the config.log file and the entire compilation output.

I have locally added a clang8.0 variant to my py-graph-tool port in MacPorts. I get this error:

:info:build In file included from graph_closeness.cc:18:
:info:build In file included from ../../../src/graph/graph_filtering.hh:21:
:info:build In file included from ../../../src/graph/graph.hh:23:
:info:build In file included from /opt/local/include/boost/python/object.hpp:9:
:info:build In file included from /opt/local/include/boost/python/object_core.hpp:14:
:info:build In file included from /opt/local/include/boost/python/call.hpp:15:
:info:build In file included from /opt/local/include/boost/python/converter/arg_to_python.hpp:10:
:info:build In file included from /opt/local/include/boost/python/to_python_indirect.hpp:10:
:info:build In file included from /opt/local/include/boost/python/object/pointer_holder.hpp:14:
:info:build In file included from /opt/local/include/boost/python/instance_holder.hpp:11:
:info:build In file included from /opt/local/include/boost/python/type_id.hpp:14:
:info:build In file included from /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/ostream:138:
:info:build In file included from /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/ios:216:
:info:build In file included from /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/__locale:15:
:info:build In file included from /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/string:505:
:info:build In file included from /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/string_view:176:
:info:build In file included from /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/__string:57:
:info:build /opt/local/libexec/llvm-8.0/bin/../include/c++/v1/algorithm:2494:5: error: static_assert failed due to requirement '__is_forward_iterator<boost::adj_list<unsigned long>::edge_iterator>::value' "std::max_element requires a ForwardIterator"
:info:build     static_assert(__is_forward_iterator<_ForwardIterator>::value,
:info:build     ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:info:build ../../../src/graph/graph_adjacency.hh:452:26: note: in instantiation of function template specialization 'std::__1::max_element<boost::adj_list<unsigned long>::edge_iterator, (lambda at ../../../src/graph/graph_adjacency.hh:453:38)>' requested here
:info:build         auto iter = std::max_element(erange.first, erange.second,
:info:build                          ^
:info:build ../../../src/graph/graph.hh:109:33: note: in instantiation of member function 'boost::adj_list<unsigned long>::shrink_to_fit' requested here
:info:build     void shrink_to_fit() { _mg->shrink_to_fit(); }
:info:build                                 ^
:info:build 2 warnings and 1 error generated.

I am using Boost 1.69, Python 3.7, Clang 8.0.

main.log

config.log