Patch from NixOS retrieved from
https://raw.githubusercontent.com/NixOS/nixpkgs/master/pkgs/development/libraries/accountsservice/drop-prefix-check-extensions.patch.

diff --git a/src/extensions.c b/src/extensions.c
index 038dcb2..830465d 100644
--- a/src/extensions.c
+++ b/src/extensions.c
@@ -121,16 +121,7 @@ daemon_read_extension_directory (GHashTable  *ifaces,
                         continue;
                 }
 
-                /* Ensure it looks like "../../dbus-1/interfaces/${name}" */
-                const gchar * const prefix = "../../dbus-1/interfaces/";
-                if (g_str_has_prefix (symlink, prefix) && g_str_equal (symlink + strlen (prefix), name)) {
-                        daemon_read_extension_file (ifaces, filename);
-                }
-                else {
-                        g_warning ("Found accounts service vendor extension symlink %s, but it must be exactly "
-                                   "equal to '../../dbus-1/interfaces/%s' for forwards-compatibility reasons.",
-                                   filename, name);
-                }
+                daemon_read_extension_file (ifaces, filename);
         }
 
         g_dir_close (dir);