64-bit configure hell

[Bill Northcott]

> From: Stan Shebs <shebs@apple.com>
> It's hard for anybody outside Apple to reproduce on Darwin right now,
> because you need an up-to-the-minute Tiger with all the trimmings,
> but you could kludge up a similar situation by taking a standard x86
> Linux config and defining a multilib with a -m codegen option that
> produces code that can't possibly run on the CPU you're using to
> build things. The tools are fine with building shlibs and even
> executables for that -m option, but you can't run any of it until
> you've moved to the right kind of CPU. (You might have to add code
> to the little conftest programs to guarantee the exectime failure,
> depending on the -m option you use.)
>
I ran into this a couple of days back.  I pulled tag apple-gcc-4020 off 
the cvs and built it.

Because I wanted fortran, libffi and libobjc-gnu I futzed about with 
the build_gcc script that sets the options on the build.  Unwittingly, 
I changed a version number in the script and it tried to build a 64bit 
libgcc with -m64 option.  It fell over at the first hurdle because I 
did not have the ppc64 headers, which I presume are unavailable outside 
Apple.

I will post the good news in a separate message.

Bill Northcott