Improve error message when ghc or ghc-pkg are mismatched or not found 
Improve error message when ghc or ghc-pkg are mismatched or not found 
sopvop/cabal,kolmodin/cabal,kosmikus/cabal,gridaphobe/cabal,bennofs/cabal,rimmington/cabal,valderman/cabal,trskop/cabal,garetxe/cabal,triplepointfive/cabal,seereason/cabal,corngood/cabal,garetxe/cabal,bennofs/cabal,randen/cabal,plow-technologies/cabal,ian-ross/cabal,lukexi/cabal,rimmington/cabal,typelead/epm,beni55/cabal,christiaanb/cabal,enolan/cabal,fpco/cabal,themoritz/cabal,mmakowski/cabal,headprogrammingczar/cabal,sopvop/cabal,plumlife/cabal,christiaanb/cabal,Peaker/cabal,anton-dessiatov/cabal,Heather/cabal,sopvop/cabal,plumlife/cabal,kolmodin/cabal,x-y-z/cabal,typelead/epm,kosmikus/cabal,seereason/cabal,themoritz/cabal,mightybyte/cabal,fugyk/cabal,fpco/cabal,eric-stanley/cabal,thomie/cabal,themoritz/cabal,corngood/cabal,beni55/cabal,lukexi/cabal,trskop/cabal,gbaz/cabal,enolan/cabal,gbaz/cabal,randen/cabal,plow-technologies/cabal,anton-dessiatov/cabal,Helkafen/cabal,thoughtpolice/cabal,ghc-android/cabal,ian-ross/cabal,thomie/cabal,headprogrammingczar/cabal,Helkafen/cabal,fugyk/cabal,edsko/cabal,Heather/cabal,martinvlk/cabal,Peaker/cabal,mydaum/cabal,edsko/cabal,thoughtpolice/cabal,x-y-z/cabal,martinvlk/cabal,mightybyte/cabal,eric-stanley/cabal,mydaum/cabal,valderman/cabal,mmakowski/cabal,ghc-android/cabal,gridaphobe/cabal,triplepointfive/cabal