diff --git a/waflib/TaskGen.py b/waflib/TaskGen.py
index ec76c1e5..b5def00d 100644
--- a/waflib/TaskGen.py
+++ b/waflib/TaskGen.py
@@ -12,7 +12,7 @@ is always postponed. To achieve this, various methods are called from the method
 
 """
 
-import copy, re
+import copy, re, os
 from waflib import Task, Utils, Logs, Errors, ConfigSet
 
 feats = Utils.defaultdict(set)