Feature or enhancement
The Trifecta Tech Foundation has sponsored work on Rust re-implementations of zlib and libbzip2.
These implementations are as fast or faster than their C counterparts (including zlib-chromium and zlib-ng). zlib-rs has seen adoption in Firefox, cargo, and many other major tools, including uv. These implementations are also "drop-in" replacements - they just require slight adjustment to linker arguments.
I think adding support for linking against zlib-rs and libbzip2-rs should be easy to do and maintain, and enable safer builds of CPython.
Eventually (not proposing this yet!), perhaps we could use zlib-rs for Windows builds to provide greater memory safety.
Related issue discussing supporting zlib-ng (mostly Unix build support is left): #91349
I have a draft PR with an implementation below: