Re: FreeBSD GCC warnings

[Bruno Haible]

Hi Yoann,

> stdio.h:20: warning: ignoring pragma: system_header
> stdlib.h:19: warning: ignoring pragma: system_header
> string.h:22: warning: ignoring pragma: system_header
> strings.h:22: warning: ignoring pragma: system_header
> [...]
> 
> This is on FreeBSD 4.10-RELEASE, gcc version 2.95.4 20020320

Indeed, #pragma GCC system_header is only supported starting with GCC 3.0.
I'm applying this.

It increases the autoconf version requirement from 2.59 to 2.60. Hope this
does not cause problems to anyone. autoconf 2.60 was released more than two
years ago.


2008-10-17  Bruno Haible  <address@hidden>

        Avoid gcc warnings because of #pragma GCC system_header on older gcc.
        * m4/include_next.m4: Require autoconf >= 2.60.
        (gl_INCLUDE_NEXT): Use #pragma GCC system_header only for GCC 3.0 or
        newer.
        Reported by Yoann Vandoorselaere <address@hidden>.

*** m4/include_next.m4.orig     2008-10-18 01:39:56.000000000 +0200
--- m4/include_next.m4  2008-10-18 01:39:50.000000000 +0200
***************
*** 1,4 ****
! # include_next.m4 serial 8
  dnl Copyright (C) 2006-2008 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
--- 1,4 ----
! # include_next.m4 serial 9
  dnl Copyright (C) 2006-2008 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
***************
*** 6,11 ****
--- 6,13 ----
  
  dnl From Paul Eggert and Derek Price.
  
+ AC_PREREQ([2.60])
+ 
  dnl Sets INCLUDE_NEXT and PRAGMA_SYSTEM_HEADER.
  dnl
  dnl INCLUDE_NEXT expands to 'include_next' if the compiler supports it, or to
***************
*** 59,65 ****
    if test $gl_cv_have_include_next = yes; then
      INCLUDE_NEXT=include_next
      if test -n "$GCC"; then
!       PRAGMA_SYSTEM_HEADER='#pragma GCC system_header'
      fi
    else
      INCLUDE_NEXT=include
--- 61,70 ----
    if test $gl_cv_have_include_next = yes; then
      INCLUDE_NEXT=include_next
      if test -n "$GCC"; then
!       dnl GCC 3.0 or newer supports #pragma GCC system_header.
!       PRAGMA_SYSTEM_HEADER='#if __GNUC__ >= 3
! #pragma GCC system_header
! #endif'
      fi
    else
      INCLUDE_NEXT=include