Add dataCast* definitions to Ptr/Array Data instances; fixes #7256
Add dataCast* definitions to Ptr/Array Data instances; fixes #7256

Patch from dreixel.

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