Re: Updating top-level autoconf to 2.59

[Paul Brook <paul at codesourcery dot com>]

On Thursday 08 February 2007 16:48, Michael Eager wrote:
> Ian Lance Taylor wrote:
> > "Joseph S. Myers" <joseph@codesourcery.com> writes:
> >> * If you want to build an explicitly cross tool despite host == target,
> >> or act like you are cross compiling despite build == host, or build a
> >> native tool (i.e. one using the native directory layout and installed as
> >> plain "gcc") despite host != target, or act like you aren't cross
> >> compiling (so can run execute tests for $host) despite build != host,
> >> these should be determined by explicit configure options; not by which
> >> of build, host and target where specified explicitly and which were
> >> defaulted.  (And not by older autoconf's experiments to see if it can
> >> execute a program built for the host.)
> >
> > I completely agree that this is how it should work.  Unfortunately,
> > this is not how autoconf {2.x,x>13} works.  I don't agree with a
> > number of the decisions made by the autoconf maintainers.  However, I
> > do think that as long we use autoconf, there is some benefit to be
> > gained by following autoconf's default behaviour.
>
> I'll stick my toe into this discussion.
>
> Much of the discussion seems to be about how autoconf should guess what
> the user intended by --host, --build, --target.  When --host or --build
> is omitted, autoconf makes guesses about what the user might have
> specified, then uses these guesses (as well as the exec test) to determine
> whether this is a native or cross build.  The result is that the user
> tries to guess how autoconf is trying to guess what the user means.

I agree. Same applies for automated build systems. Instead of just saying what 
you want, you have to reverse-engineer the autoconf guessing logic.

Paul