are there any negative effects from pinning the build to only use libc++?

The only problem is with pre-built libraries for distro-maintainers, but that is solved with the additional 'system' dependency layer I think it is reasonable to prefer LLVM, and it will be required for the eBPF work I've been doing (and will disable tables if gcc is used instead)

Ok, a lot of distros have a

libc++1

package, it seems possible to pin libc++ and have a majority of maintains do little work to support this

It will only work if LLVM itself has been recompiled with libc++, so we will still have to disable the tracing tables in the future

I don't know if I understand -- are you talking about supporting eBPF work using system toolchains?

yeah, that will probably not happen