/usr/ports/cad/vtr-verilog-to-routing/work/vtr-verilog-to-routing-596caca/vpr/src/route/rr_graph_writer.cpp:41:23: error: implicit instantiation of undefined template 'std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char> >'
    std::stringstream header;
                      ^
/usr/include/c++/v1/iosfwd:140:32: note: template is declared here
    class _LIBCPP_TEMPLATE_VIS basic_stringstream;
                               ^
1 error generated.