feenableexcept and FE_NOMASK_ENV are broken on i386 (resend)

[Bruno Haible]

Ulrich Drepper writes:

> The exception operations map directly to functionality in the CPU. ..
> This means that you won't get the exact exceptions for anything but long
> double operations.  Everything else depends on the compiler and how and
> when it decides to convert from the internal format to float or double.

Thanks for the explanation. How about documenting this limitation in
the manual? I mean, around line 1067 of arith.texi.

Bruno