Platform-indendent way of specifying line separator?

Hi Folks,

What regex (or Unicode symbol) is used to specify "line separator"?  The
regex (or Unicode symbol) must work regardless of the platform.

<pattern value="[a-zA-Z0-9]*_____"/>
                                              ^^^^^
                                             line separator regex (or
Unicode-symbol) goes here

"Zero or more alphanumeric characters followed by a new line."

Note: I do not believe that \p{Zl} is the answer.  It doesn't work with
any of the schema validators that I have tried (XML Spy, xerces).  Also,
I believe that \p{Zl} represents a single, Unicode character.  Thus it
doesn't allow multi-character line separators such as \n\r.  (But I may
be wrong)

/Roger