Mostly boring. Version.inc.in processing has a potentially interesting part which I've punted on for now (LLD_REVISION and LLD_REPOSITORY are set to empty strings for now).
lld now builds in the gn build. But no symlinks to it are created yet, so it can't be meaningfully run yet.
Now that I'm looking at this, it feels a bit awkward for lld config to be in //llvm/... rather than something like //lld:lld_config.