undo local Borland 5.6 changes

[SVN r15427]

include/boost/mpl/if.hpp

@@ -155,42 +155,8 @@ struct if_
 
 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
 
-#ifndef __BORLANDC__
-
 BOOST_MPL_AUX_VOID_SPEC(3, if_)
 
-#else // try explicit workaround for C++ Builder
-
-namespace aux_
-{
-  struct if_void_specialization
-  {
-      template< typename T1,typename T2,typename T3 , typename T4=void_,
-                typename T5=void_ >
-      struct apply
-          : if_< T1,T2,T3 > { };
-  };
-}
-
-template<>
-struct if_< void_,void_,void_ >
-    : aux_::if_void_specialization
-{
-};
-
-namespace aux
-{
-  template< typename T1,typename T2,typename T3 >
-  struct template_arity< if_< T1,T2,T3 > >
-  { static const int value = 3; };
-
-  template<>
-  struct template_arity< if_< void_,void_,void_ > >
-  { static const int value = 3; };
-}
-
-#endif 
-
 } // namespace mpl
 } // namespace boost