Porting to the changes for latest LLVM 3.6

Hi Xi Wang,
I like your project very much and I think this is very useful for analyzing unsafe compiler optimizations. I'm submitting this patch which ports the sources to compile with latest llvm 3.6.
Please review the patch and submit if you like it. Also, I have a request, can you rewrite the 'diagdiff' script to python/perl? I'm not at all familiar with ruby and I'm having hard time running that script because my system has a different version of YAML libraries for ruby.

hth,
-Aditya