Minor change

* include/mailutils/list.h (mu_list_remove)
(mu_list_remove_nd): Second arg is const.
* libmailutils/list/remove.c: Likewise.

@@ -114,10 +114,10 @@ int mu_list_insert   (mu_list_t _list, void *_item, void *_new_item,
                       int _insert_before);
   /* Remove _item from _list and deallocate any memory associated with it
      using the `destroy_item' method. */
-int mu_list_remove   (mu_list_t _list, void *_item);
+int mu_list_remove   (mu_list_t _list, const void *_item);
   /* A non-destructive version of mu_list_remove: removes the _item but does
      not deallocate it. */
-int mu_list_remove_nd  (mu_list_t _list, void *_item);
+int mu_list_remove_nd  (mu_list_t _list, const void *_item);
   /* Remove Nth element from the list. */
 int mu_list_remove_nth (mu_list_t list, size_t n);
   /* Remove Nth element from the list, non-destructive. */

@@ -24,7 +24,7 @@
 #include <mailutils/errno.h>
 
 int
-mu_list_remove (mu_list_t list, void *item)
+mu_list_remove (mu_list_t list, const void *item)
 {
   struct list_data *current;
   mu_list_comparator_t comp;
@@ -56,7 +56,7 @@ mu_list_remove (mu_list_t list, void *item)
 }
 
 int
-mu_list_remove_nd (mu_list_t list, void *item)
+mu_list_remove_nd (mu_list_t list, const void *item)
 {
   mu_list_destroy_item_t dptr = mu_list_set_destroy_item (list, NULL);
   int rc = mu_list_remove (list, item);