[XeTeX] Unicode space characters

[Arthur Reutenauer]

> ----------
> \catcode`^^^^200b=\active
> \def^^^^200b{\hskip\z at skip} 
> ----------

  Surround the snippet with \makeatletter ... \makeatother

  The @ symbol (at) isn't a legitimate part of a control sequence in a usual
TeX run (in technical terms, it has \catcode 13 = "other", where control
sequence names can contain only characters with \catcode 12 = "letter").  The
intent is to use @ only in macros defined by macro packages (.sty files, etc.),
which then prevents them from being unintentionally clobbered by users.  If,
however, you need to use some of these macros with a @ in their names, the
above first command enables you to temporarily change the category of @, by
giving it the "letter" \catcode.  You should then of course revert its \catcode
back to "other", with the second command.

	Arthur