diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -153,6 +153,14 @@
 
 CFLAGS+=	${GCOV_CFLAGS}
 
+INET_ENABLED!=	grep INET opt_inet.h || true ; echo
+INET6_ENABLED!=	grep INET6 opt_inet6.h || true ; echo
+.if empty(INET_ENABLED) || empty(INET6_ENABLED)
+CONF_CFLAGS+=	-Wno-error=unused-variable
+CONF_CFLAGS+=	-Wno-error=unused-but-set-variable
+CONF_CFLAGS+=	-Wno-error=unused-function
+.endif
+
 # Put configuration-specific C flags last so that they can override
 # the others.
 CFLAGS+=	${CONF_CFLAGS}
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -208,10 +208,8 @@
 {
 	uint32_t lleflags = 0;
 	int error = 0;
-#if defined(INET) || defined(INET6)
 	struct ether_header *eh = (struct ether_header *)phdr;
 	uint16_t etype;
-#endif
 
 	if (plle)
 		*plle = NULL;
diff --git a/sys/net/if_llatbl.c b/sys/net/if_llatbl.c
--- a/sys/net/if_llatbl.c
+++ b/sys/net/if_llatbl.c
@@ -477,9 +477,7 @@
 llentry_print_buf(const struct llentry *lle, struct ifnet *ifp, int family,
     char *buf, size_t bufsize)
 {
-#if defined(INET) || defined(INET6)
 	char abuf[INET6_ADDRSTRLEN];
-#endif
 
 	const char *valid = (lle->r_flags & RLLE_VALID) ? "valid" : "no_l2";
 	const char *upper_str = rib_print_family(llentry_get_upper_family(lle, family));
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -476,9 +476,7 @@
 rtm_get_jailed(struct rt_addrinfo *info, struct ifnet *ifp,
     struct nhop_object *nh, union sockaddr_union *saun, struct ucred *cred)
 {
-#if defined(INET) || defined(INET6)
 	struct epoch_tracker et;
-#endif
 
 	/* First, see if the returned address is part of the jail. */
 	if (prison_if(cred, nh->nh_ifa->ifa_addr) == 0) {
@@ -1003,7 +1001,6 @@
 }
 #endif
 
-#if defined(INET6) || defined(INET)
 static struct sockaddr *
 alloc_sockaddr_aligned(struct linear_buffer *lb, int len)
 {
@@ -1014,7 +1011,6 @@
 	lb->offset += len;
 	return (sa);
 }
-#endif
 
 static int
 rts_send(struct socket *so, int flags, struct mbuf *m,
@@ -1023,11 +1019,9 @@
 	struct rt_msghdr *rtm = NULL;
 	struct rt_addrinfo info;
 	struct epoch_tracker et;
-#ifdef INET6
 	struct sockaddr_storage ss;
 	struct sockaddr_in6 *sin6;
 	int i, rti_need_deembed = 0;
-#endif
 	int alloc_len = 0, len, error = 0, fibnum;
 	sa_family_t saf = AF_UNSPEC;
 	struct rib_cmd_info rc;