Use lib.makeScope for consistent package resolution

nix/default.nix

@@ -0,0 +1,15 @@
+{
+  lib,
+  gradle,
+  newScope,
+}:
+
+lib.makeScope newScope (
+  self: with self; {
+    inherit gradle;
+    buildGradlePackage = callPackage ./build-gradle-package.nix { };
+    buildMavenRepo = callPackage ./build-maven-repo.nix { };
+    gradleSetupHook = callPackage ./gradle-setup-hook.nix { };
+    gradle2nix = callPackage ./gradle2nix.nix { };
+  }
+)