Here is one configuration I got to build but I have not yet tested:
"../gcc-4.0.1/configure --prefix=$PREFIX --target=$TARGET
--with-cpu=603e --disable-nls --disable-shared --disable-threads
--enable-languages=c --without-headers --with-newlib"
"make all-gcc"
I am also trying the instructions I found for the Kuro Box at:
"http://geek.vtnet.ca/embedded/KuroBox/index.html"
The Kuro Box is an MPC8241 CPU which is a 603e core. I have not
completed their instructions so can not speak personally to how well
they work. Note that they are using gcc-3.4.3 so there could be some
deviations needed.
Frank