Index: boost/function_types/detail/pp_arity_loop.hpp
===================================================================
--- boost/function_types/detail/pp_arity_loop.hpp	(revision 49077)
+++ boost/function_types/detail/pp_arity_loop.hpp	(working copy)
@@ -89,10 +89,14 @@
 
 #     if !BOOST_PP_IS_ITERATING
 #       define BOOST_PP_FILENAME_1 BOOST_FT_AL_INCLUDE_FILE
-#     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
 #       define BOOST_PP_FILENAME_2 BOOST_FT_AL_INCLUDE_FILE
 #     else
 #       error "loops nested too deeply"
+#     endif // BOOST_PP_ITERATION_DEPTH()
 #     endif
 
 #     define BOOST_FT_arity BOOST_PP_ITERATION()