https://bugs.gentoo.org/437108

Always accept the -4 option even if we don't have IPv6 support enabled.
The relay code does this already.

--- dhcp-4.4.0/client/dhclient.c
+++ dhcp-4.4.0/client/dhclient.c
@@ -353,8 +353,8 @@
 		if (!strcmp(argv[i], "-r")) {
 			release_mode = 1;
 			/* no_daemon = 1; */
-#ifdef DHCPv6
 		} else if (!strcmp(argv[i], "-4")) {
+#ifdef DHCPv6
 			if (local_family_set && local_family != AF_INET)
 				log_fatal("Client can only do v4 or v6, not "
 					  "both.");
--- dhcp-4.4.0/server/dhcpd.c
+++ dhcp-4.4.0/server/dhcpd.c
@@ -495,8 +495,8 @@
 		} else if (!strcmp (argv [i], "-q")) {
 			quiet = 1;
 			quiet_interface_discovery = 1;
-#ifdef DHCPv6
 		} else if (!strcmp(argv[i], "-4")) {
+#ifdef DHCPv6
 			if (local_family_set && (local_family != AF_INET)) {
 				log_fatal("Server cannot run in both IPv4 and "
 					  "IPv6 mode at the same time.");