Fix OSS build
mcrouter currently does not compile, since the build system is out of sync with recent changes.
Due to the use of std::span introduced in
9a24a4ee3985aa86de726c1e3259eea416d3970c, the project now requires C++20 to build. Update the -std flag accordingly, since the existing C++17 requirement was also introduced without much fanfare in 3181213fb2f314db6619d0d5b21e3e53804bc3a1 following a similar change.
Also update Automake files to reflect some newly added project files, and link against serverdbginfo and runtime from fbthrift, since they are now required.
@stuclar has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.
@stuclar merged this pull request in facebook/mcrouter@34eb62ef403ce6619df7a527c5906ffbbb41f4ea.