Don't depend on libunwind for stack traces

[densh]

Currently we depend on system-installed version of libunwind to implement stack traces. Given that's it's a dynamic dependency, we've observed a number of issues with environment setup and configuration difficulties in the wild.

We should bake-in the libunwind (or its equivalent) into the main repo and build it as part of the runtime.

[ekrich]

Would using LLVMs unwind be an option?
https://github.com/llvm-mirror/libunwind

[ekrich]

I also found this pseudo relevant post - https://discourse.julialang.org/t/porting-julia-to-other-platforms-llvm-libunwind/575

[ekrich]

From Rust - https://github.com/rust-lang/rust/tree/master/src/libunwind