Merge pull request #19 from CodeIgniter/fileext-patch

修复设置扩展名限制为空时无法上传文件的BUG

controller/util.php

@@ -103,7 +103,8 @@ function checkExt($file,$changExt=false){
     $not_allow = $GLOBALS['auth']['ext_not_allow'];
     $ext_arr = explode('|',$not_allow);
     foreach ($ext_arr as $current) {
-        if (stristr($file,'.'.$current)){//含有扩展名
+        $current = trim($current);
+        if ($current !== '' && stristr($file,'.'.$current)){//含有扩展名
             return 0;
         }
     }