Fix SIGFPE from integer overflow during division

On some architectures (like x86_64 or i686, but not ARM for example)
overflow during integer division causes a crash due to SIGFPE.
Reproduces on a 64-bit system with:

    nix-instantiate --eval -E '(-9223372036854775807 - 1) / -1'

The only way this can happen is when the smallest possible integer is
divided by -1, so just special-case that.