We need to use a namespace Common { } there to make strict C++ compilers
like clang++ and comeau happy. I also added a slight comment about why
that is needed to the macro definition and a note that you need to use
it from the global namespace.
svn-id: r48254
I figure it the changes are harmless at worst, and making them will make it
easier to find real errors in the (still quite long) list of warnings.
svn-id: r47443
