Re: Partial autoconf transition thoughts

[Alexandre Oliva <aoliva at redhat dot com>]

On Jun 11, 2003, "Maciej W. Rozycki" <macro@ds2.pg.gda.pl> wrote:

> On 10 Jun 2003, Alexandre Oliva wrote:
>> >  Well, if I specify --host, I mean I want to use a different alias than
>> > the one that is expanded by config.sub.
>> 
>> --host has absolutely nothing to do with config.sub.  --host defaults

>  Has it?  AFAIR, whatever you specify as --host gets passed through
> config.sub before it gets assigned to $host (I'm prepending that "$" now
> to disambiguate variable references).

Err...  Yes, that's correct.  Ok, they have something to do with each
other, after all :-)

>> to --build, that defaults to the output of config.guess.  If you want
>> to override --build, just do it, and it will be propagated to host as

>  But it will be substituted by config.sub first and the original value 
> won't be propagated to $host_alias, will it?

With autoconf 2.5x, $host_alias will be set to whatever is passed as
argument to --host.  If --host is not given, $host_alias will be
blank, and $host will be the canonicalized version of the build
machine.

>  Agreed, as long as there is a way to have $host_alias and $target_alias
> set up as desired. 

We (toplevel, not autoconf) call them $host_noncanonical and
$target_noncanonical now.  autoconf no longer provides this feature.

> $ locate libbfd-2.13.2.1.so
> /usr/i386-linux/mips64el-linux/lib/libbfd-2.13.2.1.so
> /usr/i386-linux/mipsel-linux/lib/libbfd-2.13.2.1.so
> /usr/lib/libbfd-2.13.2.1.so

> Where does that "i386-linux" above come from, then?

Seems like an artifact of your install.  I don't think we use host in
install pathnames by default.

>  Well, this is probably an option, but I don't know why such a
> complication necessary.

It's necessary because of changes in autoconf that make the
propagation of command-line flags from build to host and host to
target not easily available.  If we want to avoid using the
canonicalized names, which we do, using the macros written by
Nathanael is pretty much the only way to go.

> Have you seen the dependency graphs I sent yesterday?  I believe my
> proposal is the simplest solution.

I believe Nathanael's macros are the implementation of the solution.
BTW, we already use them.  See config/acx.m4.

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                 aoliva@{redhat.com, gcc.gnu.org}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist                Professional serial bug killer