Avoid a warning about an unused variable in BOOST.

diff --git a/bundled/boost-1.70.0/include/boost/archive/iterators/wchar_from_mb.hpp b/bundled/boost-1.70.0/include/boost/archive/iterators/wchar_from_mb.hpp
index 2af8f6401f22465143978ab53d6c6bdf82edfaf8..d73c35e107b1a0b63193e4093b939413a5b313e5 100644 (file)
--- a/bundled/boost-1.70.0/include/boost/archive/iterators/wchar_from_mb.hpp
+++ b/bundled/boost-1.70.0/include/boost/archive/iterators/wchar_from_mb.hpp
@@ -174,6 +174,7 @@ void wchar_from_mb<Base>::drain(){
         m_output.m_buffer.end(),
         next_available
     );
+    (void)r;
     BOOST_ASSERT(std::codecvt_base::ok == r);
     m_output.m_next_available = next_available;
     m_output.m_next = m_output.m_buffer.begin();