Fixed atomic loads and stores on 32 bit targets.

git-svn-id: http://svn.boost.org/svn/boost/trunk@84914 b8fc166d-592f-0410-95f2-cb63ce0dd405
Added #define to detect recent modification

git-svn-id: http://svn.boost.org/svn/boost/trunk@84915 b8fc166d-592f-0410-95f2-cb63ce0dd405