When running apt-get update && apt-get upgrade, this happens:
W: Failed to fetch http://llvm.org/apt/trusty/dists/llvm-toolchain-trusty-3.6/main/binary-amd64/Packages 404 Not Found
I have no PPA and sources.list.d is empty.
Not really sure what to do now since llvm.org apt repository is offline.
If you go to http://llvm.org/apt/
You will see a message
APT mirror was temporary switched off due to excess load. We are working on bringing it back. Stay tuned!
So the llvm.org - apt - server (apt repository) is off line and will be available when they can resolve the load.
Use the version in the ubuntu repoistories until llvm.org is back online.
There is nothing harming your system at this time, you will get that warning message until the llvm repo is back up is all.
Or alternately, download the source code and manually build
http://llvm.org/releases/ and instructions here - http://llvm.org/releases/3.8.0/docs/GettingStarted.html (not ubuntu specific)
Resolved by using Software Sources GUI to disable the llvm.org repo.
