don't crash if argv[0] == NULL (#7037)
don't crash if argv[0] == NULL (#7037)

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