tests : add a C compliance test

[cebtenzzre]

This is a straightforward way to help developers realize when they make a change to llama.h that breaks C compatibility.
See PR #2847 for a recent example of this.

[cebtenzzre]

Oops, the Makefile isn't pulling in the target unless you request it explicitly. I can't even run the tests target because it's been broken since at least edd4c14:

make: *** No rule to make target 'tests/test-tokenizer-0.cpp', needed by 'tests/test-tokenizer-0'.  Stop.
make: *** Waiting for unfinished jobs....

[ggerganov]

Lets merge master and make sure CI is good