Apply 8851e27d2cb9 for 6.12.y and later

Hi Greg, Sasha,

Please consider applying the following commit for 6.12.y and later:

8851e27d2cb9 ("rust: support Rust >= 1.91.0 target spec")

It should apply cleanly.

It is not urgent, but will be needed in some weeks to support the upcoming Rust compiler versions.

Thanks!

Cheers, Miguel