In Debian sid you can install stuff like llvm-3.5-dev llvm-3.5 llvm-3.5-examples llvm-3.5-runtime llvm-3.5-tools libllvm3.5 libclang1-3.5 libclang-common-3.5-dev libclang-3.5-dev clang-3.5-examples clang-3.5 libedit-dev and maybe some more. Then start via: make LLVM_BUILD_PATH=/usr/lib/llvm-3.5/build LLVM_SRC_PATH=/usr/lib/llvm-3.5

Have fun!

In terms of building LLVM and clang, I wrote this ShutIt module a while back when trying to learn it myself:

https://github.com/ianmiell/shutit/blob/master/library/llvm/...

I bought https://www.packtpub.com/application-development/getting-sta... recently. It seems like a fairly good book. I haven't finished it yet.