free,slabtop,uptime: complain about extra ops

free, slabtop and uptime would happily take extra command line
arguments and doing nothing about them. The programs now check
optind after option processing and will give you usage screen
if there is anything extra.

References:
 procps-ng/procps#181

NEWS

@@ -18,6 +18,7 @@ procps-ng NEXT
   * vmstat: Wide mode gives wider proc columns             merge #48
   * watch: Add environment variable for interval           merge #62
   * watch: Add no linewrap option                          issue #182
+  * free,uptime,slabtop: complain about extra ops          issue #181
 
 procps-ng-3.3.16
 ----------------

free.c

@@ -341,6 +341,8 @@ int main(int argc, char **argv)
 		default:
 			usage(stderr);
 		}
+	if (optind != argc)
+	    usage(stderr);
 
 	do {
 

slabtop.c

@@ -341,6 +341,9 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	if (optind != argc)
+	    usage(stderr);
+
 	is_tty = isatty(STDIN_FILENO);
 	if (is_tty && tcgetattr(STDIN_FILENO, &saved_tty) == -1)
 		xwarn(_("terminal setting retrieval"));

uptime.c

@@ -107,6 +107,9 @@ int main(int argc, char **argv)
 			usage(stderr);
 		}
 
+	if (optind != argc)
+	    usage(stderr);
+
 	print_uptime(p);
 	return EXIT_SUCCESS;
 }