libc++abi: remove the duplicated unwind content

The unwinder has been moved into its own project setup at
http://svn.llvm.org/projects/libunwind/trunk.  This simply removes the now
duplicated content.  This move was previously discussed on llvmdev at [1].

[1] http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-January/081507.html


git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@235759 91177308-0d34-0410-b5e6-96231b3b80d8
32 files changed