Fall back on ghc-stage2 when using Windows' GHCi driver
Fall back on ghc-stage2 when using Windows' GHCi driver

Reviewers: austin, hvr, bgamari, thomie

Reviewed By: thomie

Differential Revision: https://phabricator.haskell.org/D1721

oldmanmike/ghc,nushio3/ghc,sgillespie/ghc,oldmanmike/ghc,gridaphobe/ghc,nushio3/ghc,snoyberg/ghc,shlevy/ghc,sdiehl/ghc,ezyang/ghc,vikraman/ghc,gridaphobe/ghc,tjakway/ghcjvm,sdiehl/ghc,tjakway/ghcjvm,vTurbine/ghc,vTurbine/ghc,sdiehl/ghc,sgillespie/ghc,sdiehl/ghc,shlevy/ghc,sgillespie/ghc,olsner/ghc,mettekou/ghc,mettekou/ghc,gridaphobe/ghc,vikraman/ghc,oldmanmike/ghc,tjakway/ghcjvm,olsner/ghc,vTurbine/ghc,oldmanmike/ghc,sdiehl/ghc,shlevy/ghc,sgillespie/ghc,tjakway/ghcjvm,tjakway/ghcjvm,snoyberg/ghc,ezyang/ghc,vTurbine/ghc,snoyberg/ghc,sgillespie/ghc,sdiehl/ghc,gridaphobe/ghc,vikraman/ghc,olsner/ghc,shlevy/ghc,nushio3/ghc,olsner/ghc,sdiehl/ghc,mcschroeder/ghc,mcschroeder/ghc,shlevy/ghc,oldmanmike/ghc,ezyang/ghc,sgillespie/ghc,ezyang/ghc,vTurbine/ghc,mcschroeder/ghc,mcschroeder/ghc,vikraman/ghc,snoyberg/ghc,ezyang/ghc,vikraman/ghc,olsner/ghc,nushio3/ghc,mcschroeder/ghc,oldmanmike/ghc,snoyberg/ghc,mettekou/ghc,olsner/ghc,ezyang/ghc,mettekou/ghc,shlevy/ghc,vikraman/ghc,vTurbine/ghc,mettekou/ghc,tjakway/ghcjvm,mettekou/ghc,ezyang/ghc,snoyberg/ghc,mcschroeder/ghc,mettekou/ghc,vikraman/ghc,vTurbine/ghc,snoyberg/ghc,oldmanmike/ghc,olsner/ghc,nushio3/ghc,gridaphobe/ghc,nushio3/ghc,tjakway/ghcjvm,gridaphobe/ghc,sgillespie/ghc,nushio3/ghc,mcschroeder/ghc,shlevy/ghc,gridaphobe/ghc