[XHTML2 requirements] +1 for labeledBy

At the XML2002 Conference I bumped into Emma Antunes who spontaneously
raised as a problem the fact that the html:label can only be for one control
and the control can only have one such label.

This point has been raised before, I believe by Phill Jenkins, who IIRC
suggested that a workalike for labeledBy as used in Java would fix the problem.

Al