Re: [toplevel patch] Macroize build_subdir & target_subdir, newest version

[Alexandre Oliva <aoliva@redhat.com>]

On Mar 17, 2003, Nathanael Nerode <neroden@twcny.rr.com> wrote:

> 	* config/acx.m4: Introduce _GCC_TOPLEV_NONCANONICAL_BUILD,
> 	_GCC_TOPLEV_NONCANOICAL_HOST, _GCC_TOPLEV_NONCANONICAL_TARGET,
> 	GCC_TOPLEV_SUBDIRS.
> 	* configure.in: Use GCC_TOPLEV_SUBDIRS.

This is ok, if still appropriate.  Sorry that it took so long for me
to get to it.

We still have problems in deciding what options to pass down to
sub-configures, because autoconf 2.5x's behavior in deciding whether
we're cross compiling or not depends on the actual command-line flags,
not only on the implied defaults.  Still, your patch is a step in the
right direction.

As for solving the problem of not passing --build, --host or --target
to sub-configures when it's implied, to avoid crossification :-), one
idea that was floated in the GCC Summit (was it Zack?  I seem to
recall two people independently proposing it, but I don't remember who
else did it, sorry) was to set up two different _CONFIGARGS variable
per build, host and target, and grep the autoconf version number in
the configure script to tell which version to use.  This sounds like
the only sane (even if ugly) way to avoid having to convert the entire
tree (gcc, src and what not) to the new autoconf at the same time.

-- 
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