Index: boost/fusion/functional/adapter/detail/pow2_explode.hpp
===================================================================
--- boost/fusion/functional/adapter/detail/pow2_explode.hpp	(revision 49077)
+++ boost/fusion/functional/adapter/detail/pow2_explode.hpp	(working copy)
@@ -8,7 +8,10 @@
 
 #if !defined(BOOST_PP_IS_ITERATING)
 #   error "This file has to be included by a preprocessor loop construct!"
-#elif BOOST_PP_ITERATION_DEPTH() == 1
+// For gcc 4.4 compatability, we must include the
+// BOOST_PP_ITERATION_DEPTH test inside an #else clause.
+#else // BOOST_PP_IS_ITERATING
+#if BOOST_PP_ITERATION_DEPTH() == 1
 
 #   if !defined(BOOST_FUSION_FUNCTIONAL_ADAPTER_DETAIL_POW2_EXPLODE_HPP_INCLUDED)
 #       include <boost/preprocessor/config/limits.hpp>
@@ -114,5 +117,6 @@
 #   endif
 #   endif
 
+#endif // BOOST_PP_ITERATION_DEPTH()
 #endif