The former deprecated macro RES_USE_INET6 is gone with glibc 2.30

---
 libmilter/sm_gethost.c |    6 ++++--
 sendmail/conf.c        |    6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

--- a/libmilter/sm_gethost.c
+++ b/libmilter/sm_gethost.c
@@ -51,18 +51,20 @@
 {
 	bool resv6 = true;
 	struct hostent *h;
-
+#ifdef RES_USE_INET6
 	if (family == AF_INET6)
 	{
 		/* From RFC2133, section 6.1 */
 		resv6 = bitset(RES_USE_INET6, _res.options);
 		_res.options |= RES_USE_INET6;
 	}
+#endif
 	SM_SET_H_ERRNO(0);
 	h = gethostbyname(name);
+#ifdef RES_USE_INET6
 	if (family == AF_INET6 && !resv6)
 		_res.options &= ~RES_USE_INET6;
-
+#endif
 	/* the function is supposed to return only the requested family */
 	if (h != NULL && h->h_addrtype != family)
 	{
--- a/sendmail/conf.c
+++ b/sendmail/conf.c
@@ -4249,18 +4249,20 @@
 
 # else /* HAS_GETHOSTBYNAME2 */
 	bool resv6 = true;
-
+#ifdef RES_USE_INET6
 	if (family == AF_INET6)
 	{
 		/* From RFC2133, section 6.1 */
 		resv6 = bitset(RES_USE_INET6, _res.options);
 		_res.options |= RES_USE_INET6;
 	}
+#endif
 	SM_SET_H_ERRNO(0);
 	h = gethostbyname(name);
+#ifdef RES_USE_INET6
 	if (!resv6)
 		_res.options &= ~RES_USE_INET6;
-
+#endif
 	/* the function is supposed to return only the requested family */
 	if (h != NULL && h->h_addrtype != family)
 	{