Suppress unused variable when OS does not support setuid.
Suppress unused variable when OS does not support setuid.

Signed-off-by: Edward Z. Yang <dbd597f5635f432486c5d365e9bb585b3eaa1853@mit.edu>

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