[PATCH] [libcxxabi] Add support for building and testing the unwinder.

[Dan Albert]

jroelofs: I know you had mentioned that the unwinder might be moving to compiler-rt. Any idea about timeline on that?

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Comment at: src/Unwind/CMakeLists.txt:88
@@ +87,3 @@
+    LINK_FLAGS    "${link_flags}"
+    OUTPUT_NAME   "llvmunwind"
+    VERSION       "1.0"
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Do we want it to just be libunwind? Could also build it in to libc++abi (or compiler-rt), but I assume we want it to be a different library.

http://reviews.llvm.org/D4448