I've created a Linux specific build and compiler toolchain with gcc 3.4.3. I am in the process of testing this, but up till now, all looks fine.
just
$ ARCH=nois2nommu CROSS_COMPILE=nios2-linux-uclibc- make
(for the kernel)
$ ./configure --host=nios2-linux-uclibc
$ make
for userspace with autotools.
etc, ...
It links against uclibc instead of newlib which result in smaller binaries.
http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/ph34r.gif Mail me if you're interested, I'll send the sources/archive of the toolchain.