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

include/boost/iterator/indirect_iterator.hpp

@@ -111,7 +111,7 @@ namespace iterators {
   private:
       typename super_t::reference dereference() const
       {
-# if BOOST_WORKAROUND(__BORLANDC__, < 0x5A0 )
+# if BOOST_WORKAROUND(BOOST_BORLANDC, < 0x5A0 )
           return const_cast<super_t::reference>(**this->base());
 # else
           return **this->base();