Use global applet_name instead of local versions.
diff --git a/coreutils/whoami.c b/coreutils/whoami.c
index 950f52f..983c672 100644
--- a/coreutils/whoami.c
+++ b/coreutils/whoami.c
@@ -43,7 +43,7 @@
 		puts(user);
 		exit(TRUE);
 	}
-	fprintf(stderr, "%s: cannot find username for UID %u\n", argv[0],
+	fprintf(stderr, "%s: cannot find username for UID %u\n", applet_name,
 			(unsigned) uid);
 	return(FALSE);
 }