Cheating at cross compiler setup...

So after much failure at setting up the latest GCC / GMP/ MPFR/ MPC/Bin utilities in Mac OS X 10.5.8 via manual configuration and compilation; I gave up and found an easier setup.

Mac Ports 1.9.2, with it comes a whole host of software at the simple command of the port utility.

Setting up the cross compilers for i386 elf was as simple as typing

sudo port install i386-elf-gcc

and then for nasm as well

sudo port install nasm

So from now on, my cross compilers are located in /opt/local/bin on my Mac dev box.

That was a lot easier than trying to battle with Mac OS X's semi-crippled GCC implementation.