Thanks for the answer.
But it's far from a complete rewrite, in fact if I understand correctly, the only new thing is that Apple has agreed to dual license the code so it can be included in the LLVM's libcxxabi project... but it was already opensource, so this is:
Apple double license Its already opensourced Unwinder For LLVM
An unwinder pre-C++11 never mind C++14 is most certainly a modernized rewrite to work directly with the C++ compliant Clang that is defaulting to C++11 very soon.
It already defaults to C++11 on Windows, just as Clang defaults to C99, with C11 being the future default for the C-language. The sooner people are defaulting to C++11 and C11 the better.