Making a new cross-compile target: where to begin?

["software dot au at gmail dot com" <software dot au at gmail dot com>]

Hi,

I know that some people are working on a GCC port for Minix v3, but
I'd like to work on a cross-compiler for my own purposes.  I'd like
the host and build to be i686-pc-linux-gnu, and the target to be
i[3456]86-pc-minix3.

Can anyone give me some advice on where to begin and what info I need?
 The most obvious issue is that binutils needs to be aware of the
Minix 3 a.out object file format, unless I tweak things so that a
program that converts statically linked ELF object files into a.out
object files runs automatically after a build.  I'm not sure what the
best approach would be.

There are probably some good docs out there on making a new
cross-compile target, but I haven't found them.  Do they exist, and if
yes where are they?  What new files do I need to help GCC build for a
Minix 3 target, what do I put in them, where can I learn about writing
a specs file for Minix 3, etc.

Does anyone here have a knowledge of creating a new output object
format for binutils?  I would guess that I will be patching binutils
to accept new command line options, arranging for BFD to write a.out
files, and maybe other things.  Again, not sure where to begin.

I would like to use the GCC 4 series, and binutils 2.16.1+.  The goal
is to get a cross compiler to build for a Minix 3 system on i3[456]86
systems that runs on a GNU/Linux system, so I can use it to build all
sorts of other programs for a Minix 3 system that I can't compile on
Minix 3, like most of the GNU programs, as well as the latest Perl and
Python, etc, so I can end up with a GNU/Minix 3 system.  From there
when everything is built, tested and installed, I should be able to
use the GNU/Minix 3 system itself to be self-hosting.

Thanks for your help.

James Buchanan