On Thu, Jun 07, 2012 at 01:46:28PM +0100, Ian Lynagh wrote:
>
> I propose that we remove
> Control.Concurrent.QSem
> Control.Concurrent.QSemN
> Control.Concurrent.SampleVar
> Control.Concurrent.mergeIO
> Control.Concurrent.nmergeIO
> from base.

I've just deprecated them for now, with a message saying they'll be
removed in GHC 7.8, and pointing at SafeSemaphore.

Cabal uses QSem so I think we'll have to merge in some code from SafeSemaphore as we cannot depend on that package.