DynamoRIO should build with clang

_From [reid.kle...@gmail.com](https://code.google.com/u/108532745084733145449/) on February 13, 2011 15:22:52_

I've been working on getting DynamoRIO to build with clang, since we're considering using it to try to do some extra optimization around clean calls. The thought is that we could write custom LLVM passes that do clever things for client instrumentation functions. I really only need to be able to build clients with clang in order to this, but the easiest way to achieve that is to build all of DynamoRIO with clang.

Clang also provides more helpful error messages than gcc, which is nice during development.

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=384_