array: check that we are still in the tab

If the array is modified while we are running the foreach() loop, the
tab of the array may be reallocated, so var can be totally out of the
memory: check for that.

Signed-off-by: Julien Danjou <julien@danjou.info>

common/array.h

@@ -1,6 +1,7 @@
 /*
  * array.h - useful array handling header
  *
+ * Copyright © 2009 Julien Danjou <julien@danjou.info>
  * Copyright © 2008 Pierre Habouzit <madcoder@debian.org>
  *
  * This program is free software; you can redistribute it and/or modify
@@ -32,7 +33,7 @@
 
 #define foreach(var, array) \
     for(typeof((array).tab) var = (array).tab; \
-        var < (array).tab + (array).len; \
+        var >= (array).tab && var < (array).tab + (array).len; \
         var++)
 
 #define ARRAY_FUNCS(type_t, pfx, dtor)                                      \