add multicast structures from RFC 3678 to netinet/in.h

and use _GNU_SOURCE || _BSD_SOURCE guards for all of the RFC 3678
namespace polluting things like glibc/uclibc does.

include/netinet/in.h

@@ -206,7 +206,7 @@ uint16_t ntohs(uint16_t);
 #define IP_MULTICAST_ALL   49
 #define IP_UNICAST_IF      50
 
-#ifdef _GNU_SOURCE
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
 #define MCAST_JOIN_GROUP   42
 #define MCAST_BLOCK_SOURCE 43
 #define MCAST_UNBLOCK_SOURCE      44
@@ -251,6 +251,47 @@ struct ip_mreqn
 	int imr_ifindex;
 };
 
+struct ip_mreq_source {
+	struct in_addr imr_multiaddr;
+	struct in_addr imr_interface;
+	struct in_addr imr_sourceaddr;
+};
+
+struct ip_msfilter {
+	struct in_addr imsf_multiaddr;
+	struct in_addr imsf_interface;
+	uint32_t imsf_fmode;
+	uint32_t imsf_numsrc;
+	struct in_addr imsf_slist[1];
+};
+#define IP_MSFILTER_SIZE(numsrc) \
+	(sizeof(struct ip_msfilter) - sizeof(struct in_addr) \
+	+ (numsrc) * sizeof(struct in_addr))
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+struct group_req {
+	uint32_t gr_interface;
+	struct sockaddr_storage gr_group;
+};
+
+struct group_source_req {
+	uint32_t gsr_interface;
+	struct sockaddr_storage gsr_group;
+	struct sockaddr_storage gsr_source;
+};
+
+struct group_filter {
+	uint32_t gf_interface;
+	struct sockaddr_storage gf_group;
+	uint32_t gf_fmode;
+	uint32_t gf_numsrc;
+	struct sockaddr_storage gf_slist[1];
+};
+#define GROUP_FILTER_SIZE(numsrc) \
+	(sizeof(struct group_filter) - sizeof(struct sockaddr_storage) \
+	+ (numsrc) * sizeof(struct sockaddr_storage))
+#endif
+
 struct in_pktinfo
 {
 	int ipi_ifindex;