Be a bit more sensible about choosing external OccNames
Be a bit more sensible about choosing external OccNames

Instead of chr_$wchr, we now just get $wchr.  In general, when an
OccName is system-generated, we leave it out of the final external
name, preferring to use the name of the exported parent instead (which
is necessarily a user-written name).

Names should be no less deterministic, but should be shorter and more
readable.

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