Not sure what changed (I think an upstream LLVM change, but maybe a Linux distro change), but several folks have been running into problems finding a standard C++ library when running the Carbon link step. It was actually breaking our example build when LLD didn't find the right libstdc++ install, but it finds one reliably on our build bots and sometimes for some of the developers.
For now, just remove the C++ standard library from the link. We're not doing that level of interop, and the plan is really to do that not with the system standard C++ library but by building and bundling libc++ with the installed toolchain.
Not sure what changed (I think an upstream LLVM change, but maybe a Linux distro change), but several folks have been running into problems finding a standard C++ library when running the Carbon link step. It was actually breaking our example build when LLD didn't find the right libstdc++ install, but it finds one reliably on our build bots and sometimes for some of the developers.
For now, just remove the C++ standard library from the link. We're not doing that level of interop, and the plan is really to do that not with the system standard C++ library but by building and bundling libc++ with the installed toolchain.
Left a comment explaining what's going on here.