Re: proposed gnulib-related additions to Autoconf

[Gary V. Vaughan]

Hi Paul,

Nice work!  Yes, I agree that reparenting these macros into Autoconf
is an excellent idea.  As you are soliciting feedback...

Paul Eggert wrote:
> +** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
> +  New "once-only" variants of commonly-used macros, to make 'configure'
> +  smaller and faster in common cases.

I think that putting these in Autoconf pollutes the AC_ namespace with
entries that will need to be supported in all future autoconf releases.
Two issues seem pertinent:

  i) Let's just improve AC_CHECK_HEADERS (et al) to always make configure
     smaller and faster by despatching to (undocumented internal)
     _AC_CHECK_HEADERS_ONCE when it can.
  ii) I would have thought that use of shell functions in generated
     configure scripts is safe enough by now that it should be feasible
     to shrink configure considerably by factoring common shell code
     (say, the body of AC_CHECK_HEADERS) into functions, and having the
     macros expand into appropriate calls to those functions.  Certainly,
     the next release of libtool uses shell functions extensively, and
     if it doesn't generate a backlash, it seems sensible for Autoconf
     to follow suit.

>  @uref{http://www.gnu.org/software/autoconf/, Autoconf},
> address@hidden://www.gnu.org/software/automake/, Automake}, and
> address@hidden://www.gnu.org/software/automake/, Automake},
> address@hidden://www.gnu.org/software/automake/, Gnulib}, and
>  @uref{http://www.gnu.org/software/libtool/, Libtool}.

The uref for Gnulib is wrong.

Cheers,
        Gary.
-- 
Gary V. Vaughan      ())_.  address@hidden,gnu.org}
Research Scientist   ( '/   http://tkd.kicks-ass.net
GNU Hacker           / )=   http://www.gnu.org/software/libtool
Technical Author   `(_~)_   http://sources.redhat.com/autobook

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