Makefile.defs: define HAVE_IP_MREQN on platforms with struct ip_mreqn

Makefile.defs

@@ -1722,7 +1722,7 @@ ifeq ($(OS), linux)
 	use_futex= yes
 	C_DEFS+=-DHAVE_GETHOSTBYNAME2 -DHAVE_UNION_SEMUN -DHAVE_SCHED_YIELD \
 			-DHAVE_MSG_NOSIGNAL -DHAVE_MSGHDR_MSG_CONTROL -DHAVE_ALLOCA_H \
-			-DHAVE_TIMEGM -DHAVE_SCHED_SETSCHEDULER
+			-DHAVE_TIMEGM -DHAVE_SCHED_SETSCHEDULER -DHAVE_IP_MREQN
 	ifneq ($(RAW_SOCKS), yes)
 		C_DEFS+= -DUSE_RAW_SOCKS
 	endif
@@ -1856,7 +1856,7 @@ ifeq ($(OS), freebsd)
 	C_DEFS+=-DHAVE_SOCKADDR_SA_LEN -DHAVE_GETHOSTBYNAME2 -DHAVE_UNION_SEMUN \
 		-DHAVE_SCHED_YIELD -DHAVE_MSGHDR_MSG_CONTROL \
 		-DHAVE_CONNECT_ECONNRESET_BUG -DHAVE_TIMEGM \
-		-DHAVE_NETINET_IN_SYSTM
+		-DHAVE_NETINET_IN_SYSTM -DHAVE_IP_MREQN
 	ifneq ($(RAW_SOCKS), yes)
 		C_DEFS+= -DUSE_RAW_SOCKS
 	endif
@@ -1955,7 +1955,7 @@ ifeq ($(OS), darwin)
 		-DHAVE_SCHED_YIELD -DHAVE_MSGHDR_MSG_CONTROL \
 		-DUSE_ANON_MMAP \
 		-DNDEBUG -DHAVE_CONNECT_ECONNRESET_BUG -DHAVE_TIMEGM \
-		-DUSE_SIGWAIT
+		-DUSE_SIGWAIT -DHAVE_IP_MREQN
 	# -DNDEBUG used to turn off assert (assert wants to call
 	# eprintf which doesn't seem to be defined in any shared lib
 	ifneq ($(found_lock_method), yes)