[plt-scheme] match and xml structures

There seems to be a bug with match and xml structures (these same errors occur
with html structs).

> mzscheme -l match.ss -L xml.ss xml
Welcome to MzScheme version 204.8, Copyright (c) 1995-2003 PLT
> (match (make-comment "test")
    (($ comment text) text)
    (_ #f))
STDIN::34: match: not enough fields for structure in pattern in: (struct
comment (text))
> (procedure-arity make-comment)
1

This is with the latest CVS sources.

-d