[Bug bootstrap/88668] Code generated was different for PowerPC when build!=host compared to build=host

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88668

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So the correct fix is to add --enable-targets=$enable_targets to
${realsrcdir}/configure command instead.