nameserv: avoid sockaddr_in6 with disabled IPv6 support

Fixes: 10c760a ("nameserv: require getaddrinfo() and getnameinfo()")

Author: mlichvar

nameserv.c

@@ -130,16 +130,20 @@ int
 DNS_IPAddress2Name(IPAddr *ip_addr, char *name, int len)
 {
   char *result = NULL;
-  struct sockaddr_in6 in6;
+#ifdef FEAT_IPV6
+  struct sockaddr_in6 saddr;
+#else
+  struct sockaddr_in saddr;
+#endif
   IPSockAddr ip_saddr;
   socklen_t slen;
   char hbuf[NI_MAXHOST];
 
   ip_saddr.ip_addr = *ip_addr;
   ip_saddr.port = 0;
 
-  slen = SCK_IPSockAddrToSockaddr(&ip_saddr, (struct sockaddr *)&in6, sizeof (in6));
-  if (!getnameinfo((struct sockaddr *)&in6, slen, hbuf, sizeof (hbuf), NULL, 0, 0))
+  slen = SCK_IPSockAddrToSockaddr(&ip_saddr, (struct sockaddr *)&saddr, sizeof (saddr));
+  if (!getnameinfo((struct sockaddr *)&saddr, slen, hbuf, sizeof (hbuf), NULL, 0, 0))
     result = hbuf;
 
   if (result == NULL)