--- a/win32/config_H.gc
+++ b/win32/config_H.gc
@@ -1950,12 +1950,12 @@
 #define HAS_SOCKET              /**/
 /*#define HAS_SOCKETPAIR        / **/
 /*#define HAS_SOCKADDR_SA_LEN   / **/
-/*#define HAS_SOCKADDR_IN6      / **/
+#define HAS_SOCKADDR_IN6      / **/
 #define HAS_SOCKADDR_STORAGE    /**/
 #define HAS_SIN6_SCOPE_ID       /**/
-/*#define HAS_IP_MREQ   / **/
-/*#define HAS_IP_MREQ_SOURCE    / **/
-/*#define HAS_IPV6_MREQ / **/
+#define HAS_IP_MREQ   / **/
+#define HAS_IP_MREQ_SOURCE    / **/
+#define HAS_IPV6_MREQ / **/
 /*#define HAS_IPV6_MREQ_SOURCE  / **/
 
 /* USE_STAT_BLOCKS:
--- a/win32/config.gc
+++ b/win32/config.gc
@@ -311,9 +311,9 @@
 d_inetntop='define'
 d_inetpton='define'
 d_int64_t='undef'
-d_ip_mreq='undef'
-d_ip_mreq_source='undef'
-d_ipv6_mreq='undef'
+d_ip_mreq='define'
+d_ip_mreq_source='define'
+d_ipv6_mreq='define'
 d_ipv6_mreq_source='undef'
 d_isascii='define'
 d_isblank='undef'
@@ -532,7 +532,7 @@
 d_sin6_scope_id='define'
 d_sitearch='define'
 d_snprintf='define'
-d_sockaddr_in6='undef'
+d_sockaddr_in6='define'
 d_sockaddr_sa_len='undef'
 d_sockaddr_storage='define'
 d_sockatmark='undef'
