A "tiny" (read: small) C compiler can also be found at: https://bellard.org/tcc/

It has been unmaintained for a while now, but it's still good as a starting point.

Interestingly enough it's a spin-off of a code submission for winning the international obfuscated C code contest (http://www.ioccc.org/).

Original code (covering just a subset of C) can be found here: https://bellard.org/otcc/