Use preg_replace_callback instead of preg_replace with eval. Props beaulebens. see #8689

git-svn-id: https://develop.svn.wordpress.org/trunk@10339 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/post-template.php

@@ -223,7 +223,7 @@ function get_the_content($more_link_text = null, $stripteaser = 0, $more_file =
 
 	}
 	if ( $preview ) // preview fix for javascript bug with foreign languages
-		$output =	preg_replace('/\%u([0-9A-F]{4,4})/e',	"'&#'.base_convert('\\1',16,10).';'", $output);
+		$output =	preg_replace_callback('/\%u([0-9A-F]{4})/', create_function('$match', 'return "&#" . base_convert($match[1], 16, 10) . ";";'), $output);
 
 	return $output;
 }