message: Simplify tool_paths::absolute_tools test
  ... by reusing the new [ROOT] macro.
diff: @@ -33,7 +33,6 @@ fn pathless_tools() {
  #[test]
  fn absolute_tools() {
  let target = rustc_host();
  - let root = if cfg!(windows) { r#"C:\"# } else { "/" };
  // Escaped as they appear within a TOML config file
  let config = if cfg!(windows) {
  @@ -62,14 +61,11 @@ fn absolute_tools() {
  ),
  ).build();
  - foo.cargo("build --verbose").with_stderr(&format!(
  - "\
  + foo.cargo("build --verbose").with_stderr("\
  [COMPILING] foo v0.5.0 ([CWD])
  -[RUNNING] `rustc [..] -C ar={root}bogus/nonexistent-ar -C linker={root}bogus/nonexistent-linker [..]`
  +[RUNNING] `rustc [..] -C ar=[ROOT]bogus/nonexistent-ar -C linker=[ROOT]bogus/nonexistent-linker [..]`
  [FINISHED] dev [unoptimized + debuginfo] target(s) in [..]
  -",
  - root = root,
  - )).run();
  +").run();
  }
  #[test]
  