Declare the variable before using it. props tivnet. fixes #25895 for trunk.

git-svn-id: https://develop.svn.wordpress.org/trunk@26060 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/query.php

@@ -2017,6 +2017,7 @@ class WP_Query {
 		$words = explode( ',', _x( 'about,an,are,as,at,be,by,com,for,from,how,in,is,it,of,on,or,that,the,this,to,was,what,when,where,who,will,with,www',
 			'Comma-separated list of search stopwords in your language' ) );
 
+		$stopwords = array();
 		foreach( $words as $word ) {
 			$word = trim( $word, "\r\n\t " );
 			if ( $word )