Snippets for rust 1.97.0 from Alpine riscv64

Sourced from https://build.alpinelinux.org/buildlogs/build-edge-riscv64/main/rust/rust-1.97.0-r0.log.

warning: unused import: `fs`
  --> src/bootstrap/src/core/sanity.rs:15:16
   |
15 | use std::{env, fs};
   |                ^^
   |
   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default

warning: unused variable: `run`
    --> src/bootstrap/src/core/build_steps/llvm.rs:1603:17
     |
1603 |     fn make_run(run: RunConfig<'_>) {
     |                 ^^^ help: if this is intentional, prefix it with an underscore: `_run`
     |
     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default