+echo "Checking the availability struct ip_mreq ..." >&4
+$cat >try.c <<EOF
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+int main() {
+struct ip_mreq mreq;
+return (mreq.imr_multiaddr.s_addr);
+}
+EOF
+val="$undef"
+set try; if eval $compile; then
+ val="$define"
+fi
+set d_ip_mreq; eval $setvar
+$rm_try
+
+echo " "
+echo "Checking the availability struct ip_mreq_source ..." >&4
+$cat >try.c <<EOF
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+int main() {
+struct ip_mreq_source mreq;
+return (mreq.imr_multiaddr.s_addr);
+}
+EOF
+val="$undef"
+set try; if eval $compile; then
+ val="$define"
+fi
+set d_ip_mreq_source; eval $setvar
+$rm_try
+
+echo " "
+echo "Checking the availability struct ipv6_mreq ..." >&4
+$cat >try.c <<EOF
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+int main() {
+struct ipv6_mreq mreq;
+return (mreq.ipv6mr_interface);
+}
+EOF
+val="$undef"
+set try; if eval $compile; then
+ val="$define"
+fi
+set d_ipv6_mreq; eval $setvar
+$rm_try
+
+echo " "
+echo "Checking the availability struct ipv6_mreq_source ..." >&4
+$cat >try.c <<EOF
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+int main() {
+struct ipv6_mreq_source mreq;
+return (mreq.imr_multiaddr.s_addr);
+}
+EOF
+val="$undef"
+set try; if eval $compile; then
+ val="$define"
+fi
+set d_ipv6_mreq_source; eval $setvar
+$rm_try
+
+echo " "