[PATCH] AArch64: Only enable vector math functions with -ffast-math

[Florian Weimer]

* Wilco Dijkstra:

> Only enable vector math functions with -ffast-math by adding if('fastmath').
> This uses a new annotation supported by GCC 16 [1]. If an older compiler is used,
> it will disable the math function without an error.
>
> Passes regress, OK for commit?
>
> [1] ​https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118955

Upon reconsideration, this is the least bad option we have for now, so:

Reviewed-by: Florian Weimer <fweimer@redhat.com>

Thanks,
Florian