Re: autogen.sh warnings

[Bruce Dubbs <bruce.dubbs@gmail.com>]

Felix Zielcke wrote:
> Am Mittwoch, den 09.12.2009, 17:28 -0600 schrieb Bruce Dubbs:
>> Felix Zielcke wrote:
>>> Am Mittwoch, den 09.12.2009, 16:19 -0600 schrieb Bruce Dubbs:

>>> config.guess and config.sub are used by configure.
>> Called yes, and it will give errors if not present, but is the output 
>> used?  Looking at configure, I don't think so.

> Just looking at the second result for searching config.guess in
> configure makes it pretty clear for what they're used:

> { $as_echo "$as_me:${as_lineno-$LINENO}: checking build system type" >&5
> $as_echo_n "checking build system type... " >&6; }
> if test "${ac_cv_build+set}" = set; then :
>   $as_echo_n "(cached) " >&6
> else
>   ac_build_alias=$build_alias
> test "x$ac_build_alias" = x &&
>   ac_build_alias=`$SHELL "$ac_aux_dir/config.guess"`
> test "x$ac_build_alias" = x &&
>   as_fn_error "cannot guess build type; you must specify one" "$LINENO" 5

> ac_cv_build=`$SHELL "$ac_aux_dir/config.sub" $ac_build_alias` ||
>   as_fn_error "$SHELL $ac_aux_dir/config.sub $ac_build_alias failed" "$LINENO" 5
> [...]
> build=$ac_cv_build

OK, I see now what config.sub does and it is ultimately defining host_os 
and target_cpu used by grub in several .in files.

On the other hand, config.guess is used to get build_cpu and build_os 
and I don't see that being used at all right now by grub.

One thing I think we can agree on is that tracing through 
autoconf/automake generated files is not easy.  However, it's the only 
way I know of to really understand what is going on.  The autoconf 
manual really doesn't explain it very well, at least for me.  There are 
several tutorials and books on autotools, but none that I've seen go 
into the level of complexity required by grub.

   -- Bruce