Don't print an error message if the bad option is '?'. This has been

in my tree for a long time.  bde reviewed this once upon a time and
said it was OK, iirc.  This also obviates the need to put ? in the
optstring argument to preclude the extra warning message which some
people think confuses users.  When I made my getopt cleanups of a long
time ago, this was the compromise reached.  I just neglected to commit
it until now.

lib/libc/stdlib/getopt.c

@@ -89,7 +89,7 @@ getopt(nargc, nargv, ostr)
 			return (-1);
 		if (!*place)
 			++optind;
-		if (opterr && *ostr != ':')
+		if (opterr && *ostr != ':' && optopt != BADCH)
 			(void)fprintf(stderr,
 			    "%s: illegal option -- %c\n", __progname, optopt);
 		return (BADCH);