[Bug libstdc++/80196] fenv_t not declared

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80196

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Maybe PR 40974 again, which nobody can reproduce as it only happens due to some
system-specific weirdness. We need more information about your system, what
kind of OS distro are you using? etc. etc.

Could you try adding --disable-libstdcxx-pch to the configure command?