I'm trying to compile with Visual Studio 2017, and I get these errors:

1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::fonts_stack::format::utils::fonts_stack::register_font' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(444): note: see declaration of 'format::utils::fonts_stack::register_font'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::fonts_stack::format::utils::fonts_stack::fontname' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(445): note: see declaration of 'format::utils::fonts_stack::fontname'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attr_push' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(423): note: see declaration of 'format::utils::attributes_stack::attr_push'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attrstack_push' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(424): note: see declaration of 'format::utils::attributes_stack::attrstack_push'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attrstack_drop' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(425): note: see declaration of 'format::utils::attributes_stack::attrstack_drop'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attr_pop' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(426): note: see declaration of 'format::utils::attributes_stack::attr_pop'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attr_drop_all' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(427): note: see declaration of 'format::utils::attributes_stack::attr_drop_all'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attr_pop_all' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(428): note: see declaration of 'format::utils::attributes_stack::attr_pop_all'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attr_pop_dump' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(429): note: see declaration of 'format::utils::attributes_stack::attr_pop_dump'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attr_remove' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(430): note: see declaration of 'format::utils::attributes_stack::attr_remove'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::attr_push_style' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(432): note: see declaration of 'format::utils::attributes_stack::attr_push_style'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(359): warning C4250: 'html': inherits 'format::utils::attributes_stack::format::utils::attributes_stack::register_style' via dominance
1>c:\software (third-party)\librtf\librtf-0.0.3\src\cpp\librtfcpp.h(434): note: see declaration of 'format::utils::attributes_stack::register_style'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(79): error C2385: ambiguous access of 'fonts'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(79): error C2275: 'format::fonts': illegal use of this type as an expression
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(80): error C2385: ambiguous access of 'fonts'
1>c:\software (third-party)\librtf\librtf-0.0.3\tests\01_html_converter\html.cpp(80): error C2275: 'format::fonts': illegal use of this type as an expression
WTF?