Re: _AC_CHECK_HEADER_OLD

[Ralf Wildenhues]

Hi Eric,

* Eric Blake wrote on Mon, Jun 15, 2009 at 02:33:03PM CEST:
> According to Paolo Bonzini on 6/15/2009 6:24 AM:
> > No, the right way to update _AC_CHECK_HEADER_OLD is
> > 
> > AU_DEFUN([_AC_CHECK_HEADER_OLD],
> > [AC_CHECK_HEADER([$1], [$2], [$3], [-])])
> > 
> > Ok to commit the obvious patch?
> 
> Good thing I hadn't pushed yet.  Here's my rewrite:

This rewrite causes new autoconf on gcc/gcc/configure.ac to hang.
gcc/config/acx.m4 contains

AC_DEFUN([AC_PROG_CPP_WERROR],
[AC_REQUIRE([AC_PROG_CPP])dnl
m4_define([AC_CHECK_HEADER],m4_defn([_AC_CHECK_HEADER_OLD]))
ac_c_preproc_warn_flag=yes])# AC_PROG_CPP_WERROR

and apparently the AU_DEFUN update warnings get invoked recursively, as
traces.0t grows without bound.  Not sure where to fix that.

Cheers,
Ralf

> >From ac58d9542b268f330a3c549a32170c9ba91b32ef Mon Sep 17 00:00:00 2001
> From: Eric Blake <address@hidden>
> Date: Mon, 15 Jun 2009 06:21:06 -0600
> Subject: [PATCH] Reinstate _AC_CHECK_HEADER_OLD for gcc.
> 
> * lib/autoconf/headers.m4 (_AC_CHECK_HEADER_NEW)
> (_AC_CHECK_HEADER_OLD): Provide autoupdate versions, since gcc and
> others used these undocumented macros.