static <A> S rjoin(S glue default "", Iterable<A> strings) {
  if (strings == null) ret "";
  if (strings cast Collection) {
    if (strings.size() == 1) ret str(first(strings));
  }
  new StringBuilder buf;
  Iterator<A> i = reversed(strings).iterator();
  if (i.hasNext()) {
    buf.append(i.next());
    while (i.hasNext())
      buf.append(glue).append(i.next());
  }
  ret buf.toString();
}

sS rjoin(S glue, S... strings) {
  ret join(glue, asVirtualReversedList(strings));
}

static <A> S rjoin(Iterable<A> strings, S glue) {
  ret rjoin(glue, strings);
}

sS rjoin(S[] strings) {
  ret rjoin("", strings);
}

Began life as a copy of #1000810