Question about which tools to use, bugs, the best way to implement a function, etc should go here. Don't forget to see if your question is answered in the wiki first! When in doubt post here.
Apparently not. I just looked through those headers myself, and saw that including immintrin.h will always include stdlib.h. This header is apparently not meant for freestanding environments. It makes sense given that Linux and most other kernels cannot use SSE in the kernel, and the only other use for a freestanding environment I know is for implementing a libc.
Well, guess you have to just raw-dog the builtins or go with inline assembler.