only use derefof as a Borland workaround. Eliminates warning on gcc

svn path=/trunk/boost/foreach.hpp; revision=80702
foreach: describe perils of #define-ing foreach to BOOST_FOREACH

svn path=/trunk/libs/foreach/; revision=80828
fix typo, thanks Marshall

svn path=/trunk/libs/foreach/; revision=80851
comment typo, refs #7486

svn path=/trunk/boost/foreach.hpp; revision=81148
Removed missed usage of deprecated macros in Boost.Foreach

svn path=/trunk/boost/foreach.hpp; revision=81577