I've managed to compile the GNU toolchain (binutils + gcc). gcc seems to work fine, it can properly compile source code into assembly. There are some problems with binutils that make it not able to create object files or link. I'm haven't dug deeper to see where the problem actually is.

wow, i envy you! :) i have been working on a really simple self-compiling C compiler for some time, was wondering if you are interested in adding it to your OS haha. but if GCC works fine, then i don't see a reason :d