--- a/boost/multi_array/base.hpp	2013-04-01 13:53:59.565375431 +0200
+++ b/boost/multi_array/base.hpp	2013-04-01 13:54:03.230375652 +0200
@@ -65,7 +65,7 @@
 // object creation in small-memory environments.  Thus, the objects
 // can be left undefined by defining BOOST_MULTI_ARRAY_NO_GENERATORS 
 // before loading multi_array.hpp.
-#if !BOOST_MULTI_ARRAY_NO_GENERATORS
+#ifndef BOOST_MULTI_ARRAY_NO_GENERATORS
 namespace {
   multi_array_types::extent_gen extents;
   multi_array_types::index_gen indices;