Revert Stephen Kelly's changes.

They should really wait until MPL's dependencies have dealt with his
changes.

include/boost/mpl/unpack_args.hpp

@@ -22,6 +22,7 @@
 #   include <boost/mpl/apply.hpp>
 #   include <boost/mpl/at.hpp>
 #   include <boost/mpl/size.hpp>
+#   include <boost/mpl/aux_/nttp_decl.hpp>
 #   include <boost/mpl/aux_/lambda_spec.hpp>
 #endif
 
@@ -57,8 +58,15 @@ namespace boost { namespace mpl {
 
 namespace aux {
 
+#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
 template< int size, typename F, typename Args >
 struct unpack_args_impl;
+#else
+template< BOOST_MPL_AUX_NTTP_DECL(int, size) > struct unpack_args_impl
+{
+    template< typename F, typename Args > struct apply;
+};
+#endif
 
 #define BOOST_PP_ITERATION_PARAMS_1 \
     (3,(0, BOOST_MPL_LIMIT_METAFUNCTION_ARITY, <boost/mpl/unpack_args.hpp>))
@@ -73,7 +81,12 @@ struct unpack_args
 {
     template< typename Args > struct apply
 #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
+#   if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
         : aux::unpack_args_impl< size<Args>::value,F,Args >
+#   else
+        : aux::unpack_args_impl< size<Args>::value >
+            ::template apply< F,Args >
+#   endif
     {
 #else // BOOST_MPL_CFG_NO_NESTED_FORWARDING
     {
@@ -105,6 +118,7 @@ BOOST_MPL_AUX_PASS_THROUGH_LAMBDA_SPEC(1, unpack_args)
 
 #   define i_ BOOST_PP_FRAME_ITERATION(1)
 
+#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
 
 template< typename F, typename Args >
 struct unpack_args_impl<i_,F,Args>
@@ -115,6 +129,20 @@ struct unpack_args_impl<i_,F,Args>
 {
 };
 
+#else
+
+template<> struct unpack_args_impl<i_>
+{
+    template< typename F, typename Args > struct apply
+        : BOOST_PP_CAT(apply,i_)<
+              F
+            AUX778076_UNPACKED_ARGS(i_, Args)
+            >
+    {
+    };
+};
+
+#endif
 
 #   undef i_