Support making a Win64 in-tree mingw
Support making a Win64 in-tree mingw

The Win64 mingw zip file isn't in the ghc-tarballs repo, as it's >300M.

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