Also don't use libgcc and libmain, doesn't work at all.
The two libs I have working are liblwip (IP handling) and libphy (?). But they don't give much room.
What I'd really like to see is a possibility to move individual symbols to another section. I am going to study the linker script format to try to achieve that. That way I could move all floating point stuff (outside of -lm) to flash.