utils: with-transformation: Handle more cases.

* nonguix/utils.scm (with-transformation): Skip parameters.
Avoid duplicating file system packages.

nonguix/utils.scm

@@ -64,6 +64,9 @@ matches PRED."
   (match obj
     ((? pred)
      (proc obj))
+    ;; TODO: Check if this can be handled as well.
+    ((? parameter?)
+     obj)
     ((? procedure?)
      (lambda args
        (apply values
@@ -88,6 +91,16 @@ matches PRED."
          (? origin?))
      obj)
     ((? record?)
+     (cond
+      ;; Both ‘file-systems’ and ‘boot-file-system-utilities’ services extends
+      ;; ‘profile-service-type’ with the same package, however information of
+      ;; the former one is hidden from us, causing conflict in the resulted
+      ;; profile.
+      ((and (service? obj)
+            (eq? 'boot-file-system-utilities
+                 (service-type-name (service-kind obj))))
+       obj)
+      (else
        (let* ((record-type (record-type-descriptor obj))
               (record-fields (record-type-fields record-type)))
          (apply (record-constructor record-type)
@@ -95,7 +108,7 @@ matches PRED."
                        (let* ((accessor (record-accessor record-type field))
                               (obj (accessor obj)))
                          (with-transformation proc obj pred)))
-                   record-fields))))
+                     record-fields))))))
     (_ obj)))
 
 (define (package-with-alias alias pkg)