sudo cp .travis-apt-pin.preferences /etc/apt/preferences.d/no-ubuntu-clang;
curl -sSL "http://apt.llvm.org/llvm-snapshot.gpg.key" | sudo -E apt-key add -;
echo "deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-3.9 main" | sudo tee -a /etc/apt/sources.list > /dev/null;
sudo cp .travis-apt-pin.preferences /etc/apt/preferences.d/no-ubuntu-clang;
curl -sSL "http://apt.llvm.org/llvm-snapshot.gpg.key" | sudo -E apt-key add -;
echo "deb http://apt.llvm.org/trusty/ llvm-toolchain-trusty-3.9 main" | sudo tee -a /etc/apt/sources.list > /dev/null;