Need to manually add -lstdc++ for C++ compilation

[toots]

I just finished converting ocaml-taglib to dune and I was surprised to discover that I have to manually add -lstdc++ to the linker flags here: https://github.com/savonet/ocaml-taglib/blob/master/src/config/discover.ml#L31 otherwise, the flag isn't registered with the library which prevents linking binaries using it.

Is that intended? Shouldn't dune be doing some of the lifting since it is aware that it's dealing with C++ linked code?

[ghost]

That's indeed a known issue: #3528

[toots]

Oh good, sorry I didn't check. It would be nice if that could be documented somewhere, specially the -x c++ parameter, which I've had to use in the discovery binary as well. Thanks for all the work on dune, tho, it's a great tool.

[ghost]

No problem, we should schedule this work in a few weeks. So I expect the fix to be part of 2.7 or 2.8, so hopefully not too long to wait.