Compilation fails with -DASIO_NO_DYNAMIC_BUFFER_V1 if boost::regex is available

[DinoMe]

Compilation fails at https://github.com/chriskohlhoff/asio/blob/4bcd6d5f6a6cf09d987832b9ef3a31136c6b7443/asio/include/asio/impl/read_until.hpp#L685

as details::regex_match_flags is defined at https://github.com/chriskohlhoff/asio/blob/4bcd6d5f6a6cf09d987832b9ef3a31136c6b7443/asio/include/asio/impl/read_until.hpp#L236

This is however part of the larger https://github.com/chriskohlhoff/asio/blob/4bcd6d5f6a6cf09d987832b9ef3a31136c6b7443/asio/include/asio/impl/read_until.hpp#L73

scope.

So, the compile flag ASIO_NO_DYNAMIC_BUFFER_V1 prevents the definition of regex_match_flags which is also used for v2 buffers in combination with boost::regex.

I hope this makes sense.

Thanks, Dino