Fixed segfault with now non-working -f option.

The commit to add the -d option broke getopt for -f taking an argument.

ttyclock.c

@@ -420,7 +420,7 @@ main(int argc, char **argv)
      /* Default delay */
      ttyclock->option.delay = 40000000; /* 25FPS */
 
-     while ((c = getopt(argc, argv, "tvsrcihfd:C:")) != -1)
+     while ((c = getopt(argc, argv, "tvsrcihf:d:C:")) != -1)
      {
           switch(c)
           {