Fix incorrect blocksize calculation on Win64
Fix incorrect blocksize calculation on Win64

Fixes #8839

Signed-off-by: Austin Seipp <7ea35d812706d9213868749011af1ed4fa2f6aa0@well-typed.com>

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