Accept -package-conf so cabal-install works
Accept -package-conf so cabal-install works

Really we ought to support all the old flags, but warn that they
are deprecated.

vTurbine/ghc,green-haskell/ghc,oldmanmike/ghc,christiaanb/ghc,snoyberg/ghc,siddhanathan/ghc,snoyberg/ghc,anton-dessiatov/ghc,mfine/ghc,shlevy/ghc,tjakway/ghcjvm,shlevy/ghc,olsner/ghc,da-x/ghc,nkaretnikov/ghc,christiaanb/ghc,jstolarek/ghc,elieux/ghc,ghc-android/ghc,green-haskell/ghc,mfine/ghc,spacekitteh/smcghc,da-x/ghc,holzensp/ghc,shlevy/ghc,ml9951/ghc,anton-dessiatov/ghc,ghc-android/ghc,tibbe/ghc,hferreiro/replay,GaloisInc/halvm-ghc,frantisekfarka/ghc-dsi,lukexi/ghc-7.8-arm64,siddhanathan/ghc,nushio3/ghc,vTurbine/ghc,wxwxwwxxx/ghc,tibbe/ghc,lukexi/ghc-7.8-arm64,nomeata/ghc,anton-dessiatov/ghc,holzensp/ghc,GaloisInc/halvm-ghc,tibbe/ghc,snoyberg/ghc,acowley/ghc,olsner/ghc,vikraman/ghc,da-x/ghc,bitemyapp/ghc,ml9951/ghc,holzensp/ghc,nushio3/ghc,urbanslug/ghc,nushio3/ghc,da-x/ghc,da-x/ghc,elieux/ghc,gcampax/ghc,ekmett/ghc,ml9951/ghc,ekmett/ghc,anton-dessiatov/ghc,GaloisInc/halvm-ghc,nkaretnikov/ghc,gridaphobe/ghc,mfine/ghc,mcschroeder/ghc,lukexi/ghc-7.8-arm64,ekmett/ghc,mcschroeder/ghc,tibbe/ghc,gridaphobe/ghc,bitemyapp/ghc,sgillespie/ghc,TomMD/ghc,ml9951/ghc,shlevy/ghc,nushio3/ghc,gcampax/ghc,nomeata/ghc,green-haskell/ghc,spacekitteh/smcghc,sgillespie/ghc,spacekitteh/smcghc,ezyang/ghc,bitemyapp/ghc,sgillespie/ghc,lukexi/ghc-7.8-arm64,AlexanderPankiv/ghc,lukexi/ghc,lukexi/ghc-7.8-arm64,nathyong/microghc-ghc,sdiehl/ghc,vikraman/ghc,urbanslug/ghc,vikraman/ghc,elieux/ghc,urbanslug/ghc,forked-upstream-packages-for-ghcjs/ghc,mettekou/ghc,shlevy/ghc,frantisekfarka/ghc-dsi,mfine/ghc,mcschroeder/ghc,oldmanmike/ghc,oldmanmike/ghc,ryantm/ghc,forked-upstream-packages-for-ghcjs/ghc,tjakway/ghcjvm,lukexi/ghc,frantisekfarka/ghc-dsi,gcampax/ghc,tibbe/ghc,jstolarek/ghc,GaloisInc/halvm-ghc,spacekitteh/smcghc,nushio3/ghc,ezyang/ghc,ekmett/ghc,ezyang/ghc,vTurbine/ghc,spacekitteh/smcghc,christiaanb/ghc,hferreiro/replay,nkaretnikov/ghc,TomMD/ghc,siddhanathan/ghc,hferreiro/replay,elieux/ghc,mfine/ghc,gridaphobe/ghc,anton-dessiatov/ghc,ryantm/ghc,sdiehl/ghc,ryantm/ghc,ezyang/ghc,wxwxwwxxx/ghc,christiaanb/ghc,shlevy/ghc,ghc-android/ghc,fmthoma/ghc,green-haskell/ghc,sdiehl/ghc,sdiehl/ghc,vikraman/ghc,wxwxwwxxx/ghc,vikraman/ghc,oldmanmike/ghc,nkaretnikov/ghc,TomMD/ghc,fmthoma/ghc,lukexi/ghc,nomeata/ghc,christiaanb/ghc,gcampax/ghc,sgillespie/ghc,da-x/ghc,TomMD/ghc,vTurbine/ghc,GaloisInc/halvm-ghc,hferreiro/replay,mcschroeder/ghc,mettekou/ghc,olsner/ghc,ml9951/ghc,acowley/ghc,wxwxwwxxx/ghc,fmthoma/ghc,sdiehl/ghc,snoyberg/ghc,wxwxwwxxx/ghc,mcschroeder/ghc,gcampax/ghc,siddhanathan/ghc,anton-dessiatov/ghc,oldmanmike/ghc,frantisekfarka/ghc-dsi,acowley/ghc,bitemyapp/ghc,jstolarek/ghc,sdiehl/ghc,jstolarek/ghc,forked-upstream-packages-for-ghcjs/ghc,holzensp/ghc,nomeata/ghc,mettekou/ghc,vikraman/ghc,fmthoma/ghc,forked-upstream-packages-for-ghcjs/ghc,fmthoma/ghc,mcschroeder/ghc,gridaphobe/ghc,ezyang/ghc,anton-dessiatov/ghc,holzensp/ghc,elieux/ghc,snoyberg/ghc,ghc-android/ghc,oldmanmike/ghc,snoyberg/ghc,frantisekfarka/ghc-dsi,AlexanderPankiv/ghc,olsner/ghc,GaloisInc/halvm-ghc,TomMD/ghc,sgillespie/ghc,sgillespie/ghc,wxwxwwxxx/ghc,nkaretnikov/ghc,gridaphobe/ghc,vTurbine/ghc,fmthoma/ghc,wxwxwwxxx/ghc,olsner/ghc,mfine/ghc,green-haskell/ghc,elieux/ghc,AlexanderPankiv/ghc,hferreiro/replay,mettekou/ghc,sdiehl/ghc,urbanslug/ghc,ml9951/ghc,nathyong/microghc-ghc,lukexi/ghc,nathyong/microghc-ghc,urbanslug/ghc,shlevy/ghc,hferreiro/replay,tjakway/ghcjvm,ekmett/ghc,mettekou/ghc,tjakway/ghcjvm,ezyang/ghc,elieux/ghc,nathyong/microghc-ghc,nathyong/microghc-ghc,AlexanderPankiv/ghc,TomMD/ghc,oldmanmike/ghc,ml9951/ghc,ryantm/ghc,AlexanderPankiv/ghc,sgillespie/ghc,tjakway/ghcjvm,siddhanathan/ghc,christiaanb/ghc,snoyberg/ghc,jstolarek/ghc,da-x/ghc,acowley/ghc,lukexi/ghc,olsner/ghc,gcampax/ghc,nathyong/microghc-ghc,nushio3/ghc,AlexanderPankiv/ghc,forked-upstream-packages-for-ghcjs/ghc,nomeata/ghc,TomMD/ghc,fmthoma/ghc,acowley/ghc,acowley/ghc,mettekou/ghc,gridaphobe/ghc,olsner/ghc,ghc-android/ghc,tjakway/ghcjvm,gcampax/ghc,forked-upstream-packages-for-ghcjs/ghc,mettekou/ghc,bitemyapp/ghc,nathyong/microghc-ghc,ezyang/ghc,ghc-android/ghc,ryantm/ghc,nkaretnikov/ghc,siddhanathan/ghc,vTurbine/ghc,GaloisInc/halvm-ghc,gridaphobe/ghc,tjakway/ghcjvm,forked-upstream-packages-for-ghcjs/ghc,nkaretnikov/ghc,siddhanathan/ghc,christiaanb/ghc,mfine/ghc,AlexanderPankiv/ghc,urbanslug/ghc,acowley/ghc,vikraman/ghc,urbanslug/ghc,nushio3/ghc,ghc-android/ghc,ml9951/ghc,hferreiro/replay,mcschroeder/ghc,vTurbine/ghc