[Dune] allocators... dingleton vs. instance

[Christian Engwer]

> What about other existing options for memory debugging? Good old
> efence comes to my mind. http://libcwd.sourceforge.net/ looks
> promising, too. 

first of all, I need a real allocator, so I can't use that kind of
libs anyway. And then I thought I can just as well add a little bit of
memory paranoia.

This allocator will not work as good as valgrind. About libcwd I don't
know much and can't compare.

Christian