message: Fix build script to use OUT_DIR.
diff: @@ -43,7 +43,8 @@ fn nss_dir() -> PathBuf {
  let dir = match env::var("NSS_DIR") {
  Ok(dir) => PathBuf::from(dir.trim()),
  Err(_) => {
  - let dir = Path::new("./nss");
  + let out_dir = env::var("OUT_DIR").unwrap();
  + let dir = Path::new(&out_dir).join("nss");
  if !dir.exists() {
  Command::new("hg")
  .args(&[
  @@ -54,7 +55,7 @@ fn nss_dir() -> PathBuf {
  .status()
  .expect("can't clone nss");
  }
  - let nspr_dir = Path::new("./nspr");
  + let nspr_dir = Path::new(&out_dir).join("nspr");
  if !nspr_dir.exists() {
  Command::new("hg")
  .args(&[
  