[joshuaissac]

TCC 0.9.27 can build GCC 2.95.3. You can build TCC using GNU Mes, which itself can be built using M2-Planet, which is written in a subset of C.

https://www.gnu.org/software/mes/

[fosslinux]

Furthermore, M2-Planet can be built by another C compiler written in assembly, all the way down to hex instructions.

https://github.com/oriansj/mescc-tools-seed/

[pabs3]

These projects are from the Bootstrappable Builds folks:

https://bootstrappable.org/ https://bootstrapping.miraheze.org/wiki/