Fix compatibility with PHP v7.1

Author: AngelFQC

pclzip.lib.php

@@ -1787,6 +1787,7 @@ public function privOptionDefaultThreshold(&$p_options)
         $v_memory_limit = ini_get('memory_limit');
         $v_memory_limit = trim($v_memory_limit);
         $last           = strtolower(substr($v_memory_limit, -1));
+        $v_memory_limit = preg_replace('/\s*[KkMmGg]$/', '', $v_memory_limit);
 
         if ($last == 'g') {
             //$v_memory_limit = $v_memory_limit*1024*1024*1024;