> the Gentoo uv ebuild already carries two hacks to make it possible to build uv on 32-bit platforms).

https://gitweb.gentoo.org/repo/gentoo.git/tree/dev-python/uv...

Looks like it's being built with fat LTO by default (and gentoo patched to thin LTO). Which is fine if you want to spend CI cycles once to ship executables to thousands of users. If you compile from source and run the tool maybe once then they should consider going further and run with maybe opt-level=1, lto=off; halfway between release and debug. This is how rustc itself builds some internal buildtools that get recompiled frequently relative to how often they run.