Change __BORLANDC__ to BOOST_BORLANDC, which is defined in Boost config for the Embarcadero non-clang-based compilers.

include/boost/pointee.hpp

@@ -50,7 +50,7 @@ namespace detail
       BOOST_STATIC_CONSTANT(bool, is_constant = sizeof(impl::test(*impl::x)) == 1);
 
       typedef typename mpl::if_c<
-#  if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
+#  if BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x551))
           ::boost::detail::iterator_pointee<Iterator>::is_constant
 #  else
           is_constant