Export languageExtensions as part of the API.
Export languageExtensions as part of the API.

Fixes #8200

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