package request: llvm-libunwind

[kasperk]

Gentoo and Alpine distros provide package for llvm-libunwind:

* https://packages.gentoo.org/packages/sys-libs/llvm-libunwind
* https://pkgs.alpinelinux.org/package/edge/community/x86_64/llvm-libunwind

but it seem to be missing from Ubuntu. Therefore, we build it from source tree: https://github.com/llvm/llvm-project/tree/main/libunwind with our code.

If this is an unintentional oversight, please provide this library package standalone or part of a meta toolchain package in the next release.