make it like xArg because they are different ('x' doesn't accept sign,
but 'r' does).
This fixes some warnings when building DDB with clang.
With help from: rdivacky
This commit merges the latest LLVM sources from the vendor space. It
also updates the build glue to match the new sources. Clang's version
number is changed to match LLVM's, which means /usr/include/clang/2.0
has been renamed to /usr/include/clang/2.8.
Obtained from: projects/clangbsd