update boost

linx64/include/boost/iostreams/detail/streambuf/indirect_streambuf.hpp

@@ -390,11 +390,18 @@ inline void indirect_streambuf<T, Tr, Alloc, Mode>::close_impl
         sync();
         setp(0, 0);
     }
+    #if defined(BOOST_MSVC)
+      #pragma warning(push)
+      #pragma warning(disable: 4127) // conditional expression is constant
+    #endif
     if ( !is_convertible<category, dual_use>::value ||
          is_convertible<Mode, input>::value == (which == BOOST_IOS::in) )
     {
         obj().close(which, next_);
     }
+    #if defined(BOOST_MSVC)
+      #pragma warning(pop)
+    #endif
 }
 
 //----------State changing functions------------------------------------------//