Replace eval usage in request processing with new WP_MatchesMapRegex() class usage. See #9602 props hakre.

git-svn-id: https://develop.svn.wordpress.org/trunk@11853 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/rewrite.php

@@ -299,7 +299,7 @@ function url_to_postid($url) {
 			$query = preg_replace("!^.+\?!", '', $query);
 
 			// Substitute the substring matches into the query.
-			eval("\$query = \"" . addslashes($query) . "\";");
+			$query = addslashes(WP_MatchesMapRegex::apply($query, $matches));
 			// Filter out non-public query vars
 			global $wp;
 			parse_str($query, $query_vars);