Because Chicken Scheme's compiler is self-hosting, and because it compiles to C as an intermediate form, the maintainers circumvented the bootstrapping problem by shipping generated C code for the compiler. Many *.c files feature a comment that starts like this:
Generated from optimizer.scm by the CHICKEN compiler This is *not* source code, it's a binary disguised as C source code. To resolve this bug, we need to delete these generated files from the source tarball and figure out how to bootstrap Chicken without them. Maybe someone who actively uses Chicken knows how to do this? - Dave