atf: build with the bootstrap stdenv on Darwin

pkgs/top-level/all-packages.nix

···
       };
     } ../os-specific/darwin/darwin-min-version-hook/setup-hook.sh;
 
+  ### DEVELOPMENT / TESTING TOOLS
+
+  atf = callPackage ../by-name/at/atf/package.nix {
+    stdenv =
+      # atf is a dependency of libiconv. Avoid an infinite recursion with `pkgsStatic` by using a bootstrap stdenv.
+      if stdenv.hostPlatform.isDarwin then
+        darwin.bootstrapStdenv
+      else
+        stdenv;
+  };
+
   ### DEVELOPMENT / LIBRARIES / AGDA
 
   agdaPackages = callPackage ./agda-packages.nix {