Proposal: Add concatMapM function (#2042)

[Neil Mitchell]

Hi

> The problem is that the one objector is just fundamentally opposed to
> the very process of adding stuff to the base library, for this case
> and all others.

True - I guess it must be objections to code, not to process to
actually be a problem.


> Which leaves us with 4 in favour, and a few generalists.

5, Matt Naylor as well. I really can't believe that everyone doesn't
want this, I define concatMapM in so many programs....

Thanks

Neil