Re: [PATCH] include-next, warnings: support older autoconf

[Stefano Lattarini]

Hi Eric.  Hope you don't mind hearing a minor nit ...

On Tuesday 26 July 2011, Eric Blake wrote:
> Older autoconf did not know how to peer through quoting of the
> m4 macro created by AS_VAR_PUSHDEF; while newer autoconf has
> been patched to allow typical autoconf quoting rules to still
> apply, compatibility with autoconf 2.59 requires the unquoted
> use of the macro name for all uses prior to AS_VAR_POPDEF.
> 
> absolute-header.m4 and warn-on-use.m4 already got this right.
> 
> * m4/include_next.m4 (gl_NEXT_HEADERS_INTERNAL): Use
> AS_VAR_PUSHDEF in a way that works with older autoconf.
> * m4/warnings.m4 (gl_WARN_ADD): Likewise.
> Reported by Daniel P. Berrange.
> 
> Signed-off-by: Eric Blake <address@hidden>
> ---
>  ChangeLog          |    8 ++++++++
>  m4/include_next.m4 |   12 ++++++------
>  m4/warnings.m4     |   10 +++++-----
>  3 files changed, 19 insertions(+), 11 deletions(-)
> 
> diff --git a/ChangeLog b/ChangeLog
> index cbf42ee..2752af0 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,11 @@
> +2011-07-26  Eric Blake  <address@hidden>
> +
> +     include-next, warnings: support older autoconf
> +     * m4/include_next.m4 (gl_NEXT_HEADERS_INTERNAL): Use
> +     AS_VAR_PUSHDEF in a way that works with older autoconf.
> +     * m4/warnings.m4 (gl_WARN_ADD): Likewise.
> +     Reported by Daniel P. Berrange.
> +
>  2011-07-25  Bruno Haible  <address@hidden>
> 
>       fseek, ftell: Fix doc.
> diff --git a/m4/include_next.m4 b/m4/include_next.m4
> index b3c7849..da313b3 100644
> --- a/m4/include_next.m4
> +++ b/m4/include_next.m4
> @@ -1,4 +1,4 @@
> -# include_next.m4 serial 18
> +# include_next.m4 serial 19
>  dnl Copyright (C) 2006-2011 Free Software Foundation, Inc.
>  dnl This file is free software; the Free Software Foundation
>  dnl gives unlimited permission to copy and/or distribute it,
> @@ -179,7 +179,7 @@ AC_DEFUN([gl_NEXT_HEADERS_INTERNAL],
>      [AS_VAR_PUSHDEF([gl_next_header],
>                      [gl_cv_next_]m4_defn([gl_HEADER_NAME]))
>       if test $gl_cv_have_include_next = yes; then
> -       AS_VAR_SET([gl_next_header], ['<'gl_HEADER_NAME'>'])
> +       AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>'])
>
IMHO you should add a comment here explaining why you are underquoting
(and thus implicitly stating that such underquoting is deliberate, not
a mistake); as in e.g.:

    ...
    if test $gl_cv_have_include_next = yes; then
      dnl Autoconf 2.59 requires us to underquote here.
      AS_VAR_SET(gl_next_header, ['<'gl_HEADER_NAME'>'])
      ...

And similarly for the other usages.

Thanks,
  Stefano