Migrate opt-dist to edition 2024

Cargo.lock

@@ -2567,7 +2567,6 @@ dependencies = [
  "humansize",
  "humantime",
  "log",
- "serde",
  "serde_json",
  "sysinfo",
  "tabled",

src/tools/opt-dist/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "opt-dist"
 version = "0.1.0"
-edition = "2021"
+edition = "2024"
 
 [dependencies]
 build_helper = { path = "../../build_helper" }

src/tools/opt-dist/src/main.rs

@@ -361,7 +361,10 @@ fn execute_pipeline(
 
 fn main() -> anyhow::Result<()> {
     // Make sure that we get backtraces for easier debugging in CI
-    std::env::set_var("RUST_BACKTRACE", "1");
+    unsafe {
+        // SAFETY: we are the only thread running at this point
+        std::env::set_var("RUST_BACKTRACE", "1");
+    }
 
     env_logger::builder()
         .filter_level(LevelFilter::Info)