[Bug pch/71934] pch cannot be disabled so gcc cannot be position independent

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71934

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Now having PCH around might not be useful anyways.  Someone would have to check
to see if anyone uses PCH still.