}
 
        if (argc < 4)
-               die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
+               usagef("%s <base>... -- <head> <remote> ...", argv[0]);
 
        for (i = 1; i < argc; ++i) {
                if (!strcmp(argv[i], "--"))
                        bases[bases_count++] = sha;
                }
                else
-                       warning("Cannot handle more than %zu bases. "
-                               "Ignoring %s.", ARRAY_SIZE(bases)-1, argv[i]);
+                       warning("Cannot handle more than %d bases. "
+                               "Ignoring %s.",
+                               (int)ARRAY_SIZE(bases)-1, argv[i]);
        }
        if (argc - i != 3) /* "--" "<head>" "<remote>" */
                die("Not handling anything other than two heads merge.");