message: Support Meta internal version in build.rs nightly detection
  Summary: For consistency, if someone decides to use `starlark_map` with Meta toolchain, it should be fast.
diff: @@ -43,10 +43,12 @@ fn rust_nightly() {
  // rustc 1.64.0-nightly (affe0d3a0 2022-08-05)
  // Stable output:
  // rustc 1.64.0 (a55dd71d5 2022-09-19)
  + // Meta internal output:
  + // rustc 1.64.0-dev
  let stdout = String::from_utf8(version.stdout).unwrap();
  assert!(stdout.contains("rustc"), "Sanity check");
  - let nightly = stdout.contains("nightly");
  + let nightly = stdout.contains("nightly") || stdout.contains("dev");
  if nightly {
  println!("cargo:rustc-cfg=rust_nightly");
  }
  