Fix GHC 7.8 build
Fix GHC 7.8 build

vigoo/stack,deech/stack,MichielDerhaeg/stack,MichielDerhaeg/stack,juhp/stack,Fuuzetsu/stack,mrkkrp/stack,AndrewRademacher/stack,harendra-kumar/stack,AndreasPK/stack,anton-dessiatov/stack,martin-kolinek/stack,rvion/stack,AndrewRademacher/stack,rvion/stack,Fuuzetsu/stack,luigy/stack,vigoo/stack,anton-dessiatov/stack,sjakobi/stack,luigy/stack,deech/stack,rubik/stack,harendra-kumar/stack,mrkkrp/stack,achernyak/stack,narrative/stack,achernyak/stack,rubik/stack,phadej/stack,sjakobi/stack,keent/stack,juhp/stack,Blaisorblade/stack,martin-kolinek/stack,narrative/stack,AndreasPK/stack,phadej/stack,Heather/stack,keent/stack,Heather/stack,Blaisorblade/stack