autoconf and native cross-compilation on GNU/Linux

[Sylvain BERTRAND]

Hi,
I wanted to use the build, host, target options to compile a 
"natively cross-compiled"(namely from i686-pc-linux-gnu to
i686-pc-linux-gnu) GNU/linux distribution.
But right at the beginning with the binutils I got stuck because:

1 - The build, host, target options are handled differently in 
autoconf 2.13 than in the latest versions. And binutils, gcc use 2.13
autoconf scripts.

2 - In order to detect the build of cross tools or cross compiling or 
both, configure scripts do host, target, build comparison themselves.
Then if the systems types are the same(in my case i686-pc-linux-gnu), I
cannot trigger the right behavior without deeply dive in the
configuration scripts modifying them.

I wonder what is the targeted final behavior for the build, host, 
target options: Is this already implemented is autoconf 2.57?
If so, what would involve the addition of flags and variables in 
order to force cross-compilation, building of cross-tools, or even the
canadian way?
Or, merely, do I miss something?

Sylvain