> Build failures from this change will typically look like "some `extern` functions couldn't be found; some native libraries may need to be installed or have their path specified"

Given this breaking change is known and understood in advance, and 1.5% of Rust projects still sounds like quite a lot to be affected, I feel the error could be specialized into something more useful/correct - suggesting to update their dependency on libc, or temporarily downgrade to Rust 1.92 (since upgrading may be out of their hands if it's a transitive dependency).

Though I guess most will search the error message and find the same advice either way.