Add simple-shell to build.nix

Author: hamishmack

ci.nix

@@ -125,8 +125,10 @@ dimension "Nixpkgs version" nixpkgsVersions (nixpkgsName: pinnedNixpkgsSrc:
           ghc = pkgs.buildPackages.haskell-nix.compiler.${compiler-nix-name};
         } // pkgs.lib.optionalAttrs runTests {
           inherit (build) tests tools maintainer-scripts maintainer-script-cache;
-        } // pkgs.lib.optionalAttrs (ifdLevel >= 3) {
+        } // pkgs.lib.optionalAttrs (ifdLevel >= 3) rec {
           hello = (pkgs.haskell-nix.hackage-package { name = "hello"; version = "1.0.0.2"; inherit evalPackages compiler-nix-name; }).getComponent "exe:hello";
+          # Make sure the default shell tools (hoogle) are built
+          simple-shell = (hello.project.flake {}).devShells.default;
         });
       }
       //