https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68419
--- Comment #12 from Lauri Kasanen <cand at gmx dot com> --- https://gcc.gnu.org/install/prerequisites.html "To build all languages in a cross-compiler or other configuration where 3-stage bootstrap is not performed, you need to start with an existing GCC binary (version 3.4 or later) because source code for language frontends other than C might use GCC extensions." Version 3.4 or later.