[Bug ada/112958] [12/13/14/15 regression] s-exnllf.ads etc. don't compile on 32-bit FreeBSD/x86

[gerald at pfeifer dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112958

--- Comment #6 from Gerald Pfeifer <gerald at pfeifer dot com> ---
FreeBSD i386 is on it's way out: FreeBSD 14 is the last series supporting
it; FreeBSD 15 is dropping support for it.

Can we disable libgnat (or GNAT) support during configure time?