Re-enable ghc-mod
Re-enable ghc-mod

ghc-mod-5.6 lifts the GHC 8 bounds problem.
int-index/stackage,DanielG/stackage,lwm/stackage,soenkehahn/stackage,mgajda/stackage,phaazon/stackage,alanz/stackage,phadej/stackage,brendanhay/stackage,ygale/stackage,k0ral/stackage,fpco/stackage,Daniel-Diaz/stackage,jonschoning/stackage,judah/stackage,athanclark/stackage,massysett/stackage,michalkonecny/stackage,fimad/stackage,mrkkrp/stackage,wereHamster/stackage,creichert/stackage,spencerjanssen/stackage,GregorySchwartz/stackage,ethercrow/stackage,garetxe/stackage,peti/stackage,clinty/stackage,stackbuilders/stackage,iand675/stackage,l29ah/stackage,jaspervdj/stackage,simonmichael/stackage,Shimuuar/stackage,christiaanb/stackage,mstksg/stackage,asr/stackage