Re: WORDS_BIGENDIAN not defined on sparc Solaris 10!

[Ralf Wildenhues]

Hello Paul,

* Paul Eggert wrote on Tue, Nov 27, 2007 at 06:10:37PM CET:
> 
> Thanks for catching that.  What was supposed to happen is that
> 'configure' would generate config.h code that looks like this:
[...]
> The problem is that Autoconf recently changed to a different way of
> substituting for #defines, and the old template in AC_C_BIGENDIAN wasn't
> compatible with the new way of doing this.

Wait there for a minute.  The new method is supposed to be bug-for-bug
compatible with the old one.  If it's not, then it needs fixing.

But I think it is: Autoconf 2.59 would not substitute an input file
containing:
  /* #undef FOO */

either:

cat >configure.ac <<'END'
AC_INIT
AC_CONFIG_HEADERS(config.h)
AH_TEMPLATE([
/* #undef FOO */
])
AC_DEFINE([FOO], [1], [Foo])
AC_OUTPUT
END
autoconf
autoheader
./configure
grep FOO config.h

leads to:

| /* #undef FOO */
| #define FOO 1

with both 2.59 and current code.

It's really a bug in the AC_C_BIGENDIAN code, which was introduced only
post-2.59, in
<http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=a49bbf7a83ae815b2694688ec74d6375badbaefb;hp=74416a3598b9ec94edc080787397c1c54cd117c7>

> I installed this fix:

Thanks for doing that!

Cheers,
Ralf

> 2007-11-27  Paul Eggert  <address@hidden>
> 
>       Fix AC_C_BIGENDIAN bug caused by new awk method of substitution.
>       * lib/autoconf/c.m4 (AC_C_BIGENDIAN): Don't comment out the
>       #undef as this runs afoul of our new way of creating config.h.
>       Problem reported by Jim Meyering in
>       
> <http://lists.gnu.org/archive/html/autoconf-patches/2007-11/msg00164.html>.
> 
> --- a/lib/autoconf/c.m4
> +++ b/lib/autoconf/c.m4
> @@ -1401,7 +1401,7 @@ AC_DEFUN([AC_C_BIGENDIAN],
>  #if defined __BIG_ENDIAN__
>  # define WORDS_BIGENDIAN 1
>  #elif ! defined __LITTLE_ENDIAN__
> -/* #undef WORDS_BIGENDIAN */
> +# undef WORDS_BIGENDIAN
>  #endif])dnl
>   AC_CACHE_CHECK([whether byte ordering is bigendian], [ac_cv_c_bigendian],
>     [ac_cv_c_bigendian=unknown
> 
> 
>