The latest version of g++ is written in C++. If I am not mistaken g++ 4.7.4 is the oldest version that is written in C. But it does not support the C++ version in which the latest version of g++ is written. For that you have to compile g++ 10.4.0 first. And g++ 4.7.4 cannot be compiled by the Tiny C Compiler (tcc). The total chain then becomes:

tcc 0.9.26 → tcc 0.9.27 → gcc 4.0.4 → g++ 4.7.4 → g++ 10.4.0 → g++ 13.1.0