[Bug target/83743] -mcpu=native causes gcc to exit in error if cpu is not recognized

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83743

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
How does the "old" driver know power9?  I think mixing driver and compiler
versions isn't supported.