kbuild: use getopt_long(), not its _only() variant

NetBSD lacks getopt_long_only() whereas getopt_long() works just fine.
Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/kconfig/conf.c

@@ -466,7 +466,7 @@ int main(int ac, char **av)
 	bindtextdomain(PACKAGE, LOCALEDIR);
 	textdomain(PACKAGE);
 
-	while ((opt = getopt_long_only(ac, av, "", long_opts, NULL)) != -1) {
+	while ((opt = getopt_long(ac, av, "", long_opts, NULL)) != -1) {
 		input_mode = (enum input_mode)opt;
 		switch (opt) {
 		case silentoldconfig: