[ENBD] md5sum switch

[Peter T. Breuer]

"Also sprach Peter T. Breuer:"
> Can you look to see if there is any generic way of handling a vector of
> variables in sysctl? I presume it is not obvious, or I would have done
> it.

Well - I can see how one is supposed to do it ... one can make a subdir
and let the subdir have subdirs for every device. Hmmm. Unfortunately
the whole C structure concerned (which has a field "child" for a subdir)
seems to have to be static, and yet has to control variables which are
allocated dynamically ...  owww.

Peter