maint: prefer endian.h macros to WORDS_BIGENDIAN

[Collin Funk]

A while ago I added the endian.h gnulib module to simplify byte-order
conversions. This patch gets rid of the rest of autoconf's
WORDS_BIGENDIAN macro and uses the standardized endian.h macros.

Will push in a bit if there are no objections.

Collin


>From 1dc6de03bb8cd6b1a7f313ec81ee935004f898e9 Mon Sep 17 00:00:00 2001
Message-ID: <1dc6de03bb8cd6b1a7f313ec81ee935004f898e9.1751598116.git.collin.fu...@gmail.com>
From: Collin Funk <collin.fu...@gmail.com>
Date: Thu, 3 Jul 2025 19:48:44 -0700
Subject: [PATCH] maint: prefer endian.h macros to WORDS_BIGENDIAN

* src/od.c: Include endian.h.
(WORDS_BIGENDIAN): Remove definition.
(main): Use BYTE_ORDER, BIG_ENDIAN, LITTLE_ENDIAN instead of
WORDS_BIGENDIAN. Fix formatting.
* src/blake2/blake2-impl.h: Include endian.h. Use BYTE_ORDER and
LITTLE_ENDIAN instead of WORDS_BIGENDIAN.
---
 src/blake2/blake2-impl.h |  3 ++-
 src/od.c                 | 17 +++++++----------
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/src/blake2/blake2-impl.h b/src/blake2/blake2-impl.h
index 02a1b8fec..bddd4f884 100644
--- a/src/blake2/blake2-impl.h
+++ b/src/blake2/blake2-impl.h
@@ -15,7 +15,8 @@
 #ifndef BLAKE2_IMPL_H
 #define BLAKE2_IMPL_H
 
-#ifndef WORDS_BIGENDIAN
+#include <endian.h>
+#if BYTE_ORDER == LITTLE_ENDIAN
 # define NATIVE_LITTLE_ENDIAN 1
 #endif
 
diff --git a/src/od.c b/src/od.c
index b64f083c6..be7d06751 100644
--- a/src/od.c
+++ b/src/od.c
@@ -19,6 +19,7 @@
 #include <config.h>
 
 #include <ctype.h>
+#include <endian.h>
 #include <float.h>
 #include <stdio.h>
 #include <getopt.h>
@@ -301,10 +302,6 @@ static enum size_spec const fp_type_size[] =
 #endif
   };
 
-#ifndef WORDS_BIGENDIAN
-# define WORDS_BIGENDIAN 0
-#endif
-
 /* Use native endianness by default.  */
 static bool input_swap;
 
@@ -1756,12 +1753,12 @@ main (int argc, char **argv)
         case ENDIAN_OPTION:
           switch (XARGMATCH ("--endian", optarg, endian_args, endian_types))
             {
-              case endian_big:
-                  input_swap = ! WORDS_BIGENDIAN;
-                  break;
-              case endian_little:
-                  input_swap = WORDS_BIGENDIAN;
-                  break;
+            case endian_big:
+              input_swap = BYTE_ORDER != BIG_ENDIAN;
+              break;
+            case endian_little:
+              input_swap = BYTE_ORDER != LITTLE_ENDIAN;
+              break;
             }
           break;
 
-- 
2.50.0