$ curl -O http://llvm.org/releases/3.7.0/llvm-3.7.0.src.tar.xz
$ tar xf llvm-3.7.0.src.tar.xz
$ cd llvm-3.7.0.src/projects/
-llvm-3.7.0.src/projects $ curl http://llvm.org/releases/3.7.0/libcxxabi-3.7.0.src.tar.xz | tar xJf -
-llvm-3.7.0.src/projects $ mv libcxxabi-3.7.0.src libcxxabi
llvm-3.7.0.src/projects $ curl http://llvm.org/releases/3.7.0/libunwind-3.7.0.src.tar.xz | tar xJf -
llvm-3.7.0.src/projects $ mv libunwind-3.7.0.src libunwind
llvm-3.7.0.src/projects $ mkdir libunwind/build