combine_latest fails build with MSVC 19.34.31935.0 when C++ standard is set to 17 about rxcpp

[juhanisimola-yousician]

I fixed this and some Clang issues at https://github.com/YousicianGit/RxCpp/pull/1/files

[xiaoxiaok]

Add util to apply in surely may fix this problem just as following

template<class... T>
inline auto surely(const std::tuple<T...>& tpl)
    -> decltype(util::apply(tpl, detail::surely())) {
    return      util::apply(tpl, detail::surely());
}

[juhanisimola-yousician]

Thanks, that worked.