Fix conflict with macros defined in kern/queue.h
https://trac.macports.org/ticket/60088
--- src/tuntap.h.orig	2014-11-04 10:35:06.000000000 +1100
+++ src/tuntap.h	2021-12-23 16:02:21.000000000 +1100
@@ -170,10 +170,10 @@ class tuntap_mbuf_queue {
 
 		/* enqueue an mbuf. returns true if there was space left, so the mbuf could be
 		 * queued, false otherwise */
-		bool enqueue(mbuf_t mb);
+		bool mb_enqueue(mbuf_t mb);
 
 		/* tries to dequeue the next mbuf. If the queue is empty, NULL is returned */
-		mbuf_t dequeue();
+		mbuf_t mb_dequeue();
 
 		/* makes the queue empty, discarding any queue packets */
 		void clear();
--- src/tuntap.cc.orig	2014-11-04 10:35:06.000000000 +1100
+++ src/tuntap.cc	2021-12-23 16:02:36.000000000 +1100
@@ -210,7 +210,7 @@ tuntap_mbuf_queue::~tuntap_mbuf_queue()
 }
 
 bool
-tuntap_mbuf_queue::enqueue(mbuf_t mb)
+tuntap_mbuf_queue::mb_enqueue(mbuf_t mb)
 {
 	if (size == QUEUE_SIZE)
 		return false;
@@ -229,7 +229,7 @@ tuntap_mbuf_queue::enqueue(mbuf_t mb)
 }
 
 mbuf_t
-tuntap_mbuf_queue::dequeue()
+tuntap_mbuf_queue::mb_dequeue()
 {
 	mbuf_t ret;
 
@@ -556,7 +556,7 @@ tuntap_interface::cdev_read(uio_t uio, i
 	while (cur_mbuf == NULL) {
 		dprintf("tuntap: fetching new mbuf\n");
 
-		cur_mbuf = send_queue.dequeue();
+		cur_mbuf = send_queue.mb_dequeue();
 		if (cur_mbuf == NULL) {
 			/* nothing in queue, block or return */
 			if (!block_io) {
@@ -800,7 +800,7 @@ tuntap_interface::if_output(mbuf_t m)
 
 		auto_lock l(&lock);
 
-		if (!send_queue.enqueue(pkt)) {
+		if (!send_queue.mb_enqueue(pkt)) {
 			mbuf_freem(pkt);
 			mbuf_freem_list(m);
 			return ENOBUFS;