add config.haskell.buildCoreLibraries option
haskell-mtl: update for 7.8.3/buildCorePackages
haskell-hslogger-template: fix for new mtl
haskell-time-recurrence: fix for new mtl
haskell-wizards: fix for new mtl
haskell-tables: fix for new mtl
haskell-cmdtheline: fix for new mtl
haskell-machines: fix for new mtl
haskell-singletons: fix for new mtl