[boost] constness in barrier.hpp

Hi all, simple patch to make const the private member m_threshold in class barrier Regards Gaetano --- barrier.hpp.original 2011-12-22 12:05:05.921720854 +0100 +++ barrier.hpp 2011-12-22 12:05:36.936205847 +0100 @@ -52,7 +52,7 @@ private: mutex m_mutex; condition_variable m_cond; - unsigned int m_threshold; + const unsigned int m_threshold; unsigned int m_count; unsigned int m_generation; };