From a70007dbdfa4a6b85bac31f8de139b1b02f0ffc3 Mon Sep 17 00:00:00 2001
From: Yakun Xu <xyk@google.com>
Date: Wed, 12 Feb 2020 23:42:50 +0800
Subject: [PATCH] [build] auto detect big endian (#4551)

---
 configure.ac                 | 2 ++
 src/core/common/encoding.hpp | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/configure.ac b/configure.ac
index d9f51b89d..9122f469c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -202,6 +202,8 @@ AC_PROG_CXX_C_O
 
 AM_PROG_AS
 
+AC_C_BIGENDIAN
+
 # Check for other compiler toolchain tools.
 
 AC_CHECK_TOOL(AR, ar)
diff --git a/src/core/common/encoding.hpp b/src/core/common/encoding.hpp
index 0d4ba72cb..8f2858406 100644
--- a/src/core/common/encoding.hpp
+++ b/src/core/common/encoding.hpp
@@ -37,8 +37,13 @@
 #include "openthread-core-config.h"
 
 #ifndef BYTE_ORDER_BIG_ENDIAN
+#if defined(WORDS_BIGENDIAN) || \
+    defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define BYTE_ORDER_BIG_ENDIAN 1
+#else
 #define BYTE_ORDER_BIG_ENDIAN 0
 #endif
+#endif
 
 #include <limits.h>
 #include <stdint.h>