To counter that, they're working on a bootstrap chain that starts with a tiny 500 byte hex editor and ends with a compiler that can build the GNU toolchain.
Re:Guix Reduces Bootstrap Seed by Half
by newnewpdro on Wednesday October 09, 2019 @07:53AM
(#21202269)
That's the whole point of these projects - they're preventing that type of attack.
If you implement your bootstrap C compiler entirely in machine code for instance, it doesn't matter if the "original C compiler" is compromised, since it's not being compiled.
(Ken Thompson coined the term and knows how to do it.)