message: Publically export OS_ENV
  This needs to be public to allow rustup to cleanly call the from family
  of functions but still benefit from the Windows specific codepath.
diff: @@ -53,7 +53,7 @@ pub trait Env {
  /// is using. Code that is not performing in-process threaded testing requiring
  /// isolated rustup/cargo directories does not need this trait or the _from
  /// functions.
  -struct OsEnv {}
  +pub struct OsEnv {}
  impl Env for OsEnv {
  fn home_dir(&self) -> Option<PathBuf> {
  home_dir_inner()
  @@ -66,7 +66,7 @@ impl Env for OsEnv {
  }
  }
  -static OS_ENV: OsEnv = OsEnv {};
  +pub static OS_ENV: OsEnv = OsEnv {};
  /// Returns the path of the current user's home directory if known.
  ///
  