v1.7.0
https://github.com/libunwind/libunwind/commit/688caaf6ef9853cc26ad8bd1706804d48a0df0bc

Apply https://github.com/libunwind/libunwind/pull/457
Apply https://github.com/libunwind/libunwind/pull/455
Apply https://github.com/libunwind/libunwind/pull/460
