List of best mirrors for IP address 3.15.17.137, located in an unknown country.
I am very sorry, but no mirror was found. Feel free to download directly:
http://mirrordirector-mb.raspbian.org/multiarch/pool/main/l/llvm-toolchain-6.0/libclang-common-6.0-dev_6.0.1-10+rpi1_arm64.deb