[Bug ipa/119012] [riscv] Bootstrap comparison failure: gcc/rust/rust-lex.o differs

[rsworktech at outlook dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119012

--- Comment #19 from Levi Zim <rsworktech at outlook dot com> ---
Another trigger flag, a little surprisingly, is
-ffile-prefix-map=/build/gcc/src=/usr/src/debug/gcc in CFLAGS