The problem is that the Arduino M0 isn't officially supported, because I haven't yet had a chance to test uLisp with a board. For a full list see:
However, assuming the board is similar to the other SAM/SAMD boards it should work if you provide a definition for it in the uLisp source. If you find the section of the source starting with the comment:
there's a series of #defines for each supported board. You could try changing:
which might work. Let me know how you get on.