Adjust endianness detection

__BYTE_ORDER__ isn't available in older gcc, unfortunately.

diff --git a/configure.ac b/configure.ac
index e5e834f39143c0f83132a81c3722866f182ed75d..27d6fa3893a6951e13e1cb2657081ff531485bcf 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -5,6 +5,7 @@ AC_CONFIG_SRCDIR([src/wim.c])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([build-aux])
 AM_INIT_AUTOMAKE([-Wall -Werror subdir-objects foreign])
+AC_C_BIGENDIAN
 m4_ifdef([AM_PROG_AR], [AM_PROG_AR])
 LT_INIT
 

diff --git a/include/wimlib/compiler-gcc.h b/include/wimlib/compiler-gcc.h
index 46983308ec8f6b2e1bae224d2b971e4bccdd361b..cb42c894800e668bf24c4098fa567a97f4e84121 100644 (file)
--- a/include/wimlib/compiler-gcc.h
+++ b/include/wimlib/compiler-gcc.h
@@ -27,7 +27,17 @@
 #define inline                 inline __attribute__((always_inline))
 #define noinline               __attribute__((noinline))
 
-#define CPU_IS_BIG_ENDIAN      (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+/* Newer gcc supports __BYTE_ORDER__.  Older gcc doesn't.  */
+#ifdef __BYTE_ORDER__
+#  define CPU_IS_BIG_ENDIAN    (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
+#elif defined(HAVE_CONFIG_H)
+#  include "config.h"
+#  ifdef WORDS_BIGENDIAN
+#    define CPU_IS_BIG_ENDIAN 1
+#  else
+#    define CPU_IS_BIG_ENDIAN 0
+#  endif
+#endif
 
 #if defined(__x86_64__) || defined(__i386__)
 #  define UNALIGNED_ACCESS_SPEED 3

diff --git a/include/wimlib/compiler.h b/include/wimlib/compiler.h
index 11eaa2398f2a560dd336872c1e355a9d2d955fcf..4bd92d78dee0bffcade4ff5b8247ef7f63094737 100644 (file)
--- a/include/wimlib/compiler.h
+++ b/include/wimlib/compiler.h
@@ -59,7 +59,7 @@
 #endif
 
 #ifndef CPU_IS_BIG_ENDIAN
-#  error "missing required definition of CPU_IS_BIG_ENDIAN"
+#  error "missing required endianness definition"
 #endif
 
 #define CPU_IS_LITTLE_ENDIAN (!CPU_IS_BIG_ENDIAN)