network: added preprocessor guard around the port sharing feature

Signed-off-by: Leonardo Alminana <[email protected]>

src/flb_network.c

@@ -189,7 +189,12 @@ int flb_net_socket_share_port(flb_sockfd_t fd)
     int on = 1;
     int ret;
 
+#ifdef SO_REUSEPORT
     ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
+#else
+    ret = -1;
+#endif
+
     if (ret == -1) {
         flb_errno();
         return -1;