Use bootstrap compiler to check materialisations

Author: andreabedini

overlays/bootstrap.nix

@@ -1124,7 +1124,7 @@ in {
       let
         # This compiler-nix-name will only be used to build nix-tools and cabal-install
         # when checking materialization of alex, happy and hscolour.
-        compiler-nix-name = "ghc865";
+        compiler-nix-name = buildBootstrapper.compilerNixName;
         # The ghc boot compiler to use to compile alex, happy and hscolour
         ghc = final.buildPackages.haskell-nix.bootstrap.compiler."${buildBootstrapper.compilerNixName}";
         ghcOverride = ghc // { isHaskellNixCompiler = ghc.isHaskellNixBootCompiler; };