message: Test cargo build being resilient to filesystem loop
diff: @@ -1668,7 +1668,7 @@ package `test v0.0.0 ([CWD])`
  }
  #[cargo_test]
  -/// Make sure broken symlinks don't break the build
  +/// Make sure broken and loop symlinks don't break the build
  ///
  /// This test requires you to be able to make symlinks.
  /// For windows, this may require you to enable developer mode.
  @@ -1681,6 +1681,10 @@ fn ignore_broken_symlinks() {
  .file("Cargo.toml", &basic_bin_manifest("foo"))
  .file("src/foo.rs", &main_file(r#""i am foo""#, &[]))
  .symlink("Notafile", "bar")
  + // To hit the symlink directory, we need a build script
  + // to trigger a full scan of package files.
  + .file("build.rs", &main_file(r#""build script""#, &[]))
  + .symlink_dir("a/b", "a/b/c/d/foo")
  .build();
  p.cargo("build").run();
  