bignum.c:554
VALUE
rb_ll2big(n)
    LONG_LONG n;
{
    long neg = 0;
    VALUE big;

    if (n < 0) {
	n = -n;
	neg = 1;
    }
    big = rb_ull2big(n);
    if (neg) {
	RBIGNUM(big)->sign = 0;
    }
    return big;
}
