Fix more compiler warnings.

diff --git a/misc/mklost+found.c b/misc/mklost+found.c
index fa77930..027c899 100644
--- a/misc/mklost+found.c
+++ b/misc/mklost+found.c
@@ -45,6 +45,7 @@
 	fprintf (stderr, "mklost+found %s (%s)\n", E2FSPROGS_VERSION,
 		 E2FSPROGS_DATE);
 	if (argc != 1) {
+		(void)argv; /* avoid unused argument warning */
 		fprintf (stderr, _("Usage: mklost+found\n"));
 		exit(1);
 	}