From ed1a88e26380de240f9018984d4291ba57a2f52a Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Wed, 27 Feb 2019 10:27:56 +1100
Subject: [PATCH] extmod/modlwip: Don't require a port to define concurrency
 macros.

---
 extmod/modlwip.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/extmod/modlwip.c b/extmod/modlwip.c
index 83104a487f..1b8caa8944 100644
--- a/extmod/modlwip.c
+++ b/extmod/modlwip.c
@@ -69,6 +69,13 @@
 #define ip_reset_option(pcb, opt) ((pcb)->so_options &= ~(opt))
 #endif
 
+// A port can define these hooks to provide concurrency protection
+#ifndef MICROPY_PY_LWIP_ENTER
+#define MICROPY_PY_LWIP_ENTER
+#define MICROPY_PY_LWIP_REENTER
+#define MICROPY_PY_LWIP_EXIT
+#endif
+
 #ifdef MICROPY_PY_LWIP_SLIP
 #include "netif/slipif.h"
 #include "lwip/sio.h"