Rollup merge of #80461 - rust-lang:tmandry-patch-1, r=Mark-Simulacrum
Rollup merge of #80461 - rust-lang:tmandry-patch-1, r=Mark-Simulacrum

Add llvm-libunwind change to bootstrap CHANGELOG

From #77703.

This doesn't need a `changelog-seen` version bump because the old values aren't accepted anymore, meaning anyone who was using this had to change it already.

r? ``@Mark-Simulacrum``

graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust