Index: apt-pkg/contrib/weakptr.h
===================================================================
--- apt-pkg/contrib/weakptr.h
+++ apt-pkg/contrib/weakptr.h	2011-12-13 07:35:28.114762886 +0100
@@ -55,7 +55,7 @@
     ~WeakPointable() {
         std::set<WeakPointable**>::iterator iter = pointers.begin();
         while (iter != pointers.end())
-            **(iter++) = NULL;
+            **(iter++) = 0;
     }
 };