Re: gcc-4.3, glibc and AC_PROG_CC_STDC

[Ralf Wildenhues]

Hello Bruno,

* Bruno Haible wrote on Sat, Feb 10, 2007 at 11:44:43PM CET:
>
> glibc's <wchar.h> from 2.3.x up to the most recent ones has a bug
[...]

> I think autoconf should do something about it.
> 
> There are two possibilities:
>   - Modify AC_PROG_CC_STDC so that it doesn't activate --std=gnu99 in this
>     case,

This sounds far too drastic IMHO.  It would be seriously silly if
the GNU system would detect its own system as non-C99 one just for
one C99 related bug.  There are loads of useful C99 features and
programs that make use of them, independent of this issue.

Wait.  Did you mean for it to activate --std=c99 instead, or gnu89?

>   - Modify AC_CHECK_HEADERS so that it reports <wchar.h> missing in this case.

- Write a gl_HEADER_WCHAR_H that DTRT.  Use that.  If it's good,
  suggest it for inclusion in Autoconf as AC_HEADER_WCHAR_H.

Isn't GCC's fixincludes meant for exactly this sort of issues?
Why can't it be "fixed" there?  I mean, this issue is one that
touches all users of GCC, not just those that also happen to use
Autoconf.  And a fix there would kill the issue for all of them
(next to the obvious fix place: in (distributors' versions of)
glibc).

If the absolute header inclusion technique employed by gnulib is
preventing the fixinclude thingy to work, then I suggest that
gnulib be fixed.  I haven't checked though whether that is the
case here.

>  - gcc-4.3's behaviour is not likely to change (they have made the change
>    precisely for implementing ISO C 99 more closely),
>  - gcc-4.3 should be released in spring 2008,

Hmm.  Given that there is still discussion and work on GCC for this
topic anyway[1], I don't think Autoconf should be doing anything just
yet.

Cheers,
Ralf

[1] <http://gcc.gnu.org/ml/gcc-patches/2007-02/msg00789.html>