From b1f1ea7859bf57aa2c81782c41dbe5866f5598f5 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Thu, 4 Jan 2024 08:46:59 +1100
Subject: [PATCH] AP_Networking: don't build lwip code if not needed

this saves a bit of compile time, but also means devs not doing
networking don't need to update the submodules
---
 libraries/AP_Networking/AP_Networking_Config.h     | 2 ++
 libraries/AP_Networking/lwip_hal/arch/sys_arch.cpp | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/libraries/AP_Networking/AP_Networking_Config.h b/libraries/AP_Networking/AP_Networking_Config.h
index ea77791a2b..b9fdbd6fd3 100644
--- a/libraries/AP_Networking/AP_Networking_Config.h
+++ b/libraries/AP_Networking/AP_Networking_Config.h
@@ -50,6 +50,8 @@
 #define AP_NETWORKING_SOCKETS_ENABLED AP_NETWORKING_ENABLED
 #endif
 
+#define AP_NETWORKING_NEED_LWIP (AP_NETWORKING_BACKEND_CHIBIOS || AP_NETWORKING_BACKEND_PPP)
+
 // ---------------------------
 // IP Features
 // ---------------------------
diff --git a/libraries/AP_Networking/lwip_hal/arch/sys_arch.cpp b/libraries/AP_Networking/lwip_hal/arch/sys_arch.cpp
index d9b517b47f..83053a9ee2 100644
--- a/libraries/AP_Networking/lwip_hal/arch/sys_arch.cpp
+++ b/libraries/AP_Networking/lwip_hal/arch/sys_arch.cpp
@@ -4,6 +4,9 @@
  */
 
 #include <AP_HAL/AP_HAL.h>
+#include <AP_Networking/AP_Networking_Config.h>
+
+#if AP_NETWORKING_NEED_LWIP
 #include <AP_HAL/Semaphores.h>
 #include <AP_Math/AP_Math.h>
 
@@ -385,3 +388,5 @@ sys_arch_unprotect(sys_prot_t pval)
     }
 }
 
+#endif // AP_NETWORKING_NEED_LWIP
+