flint_mpn_gcd_vec

Sets $(g, \ell)$ to the greatest common divisor of $(g, \mathit{gn})$ and the len values $(\mathit{xp}_i, \mathit{xn}_i)$, and returns its length $\ell$ (0 if all are zero). The values are given by pointer, so that they need not be contiguous or copied, and must be normalised (top limb nonzero), with $\mathit{xn}_i = 0$ for zero; $\mathit{gn} = 0$ means that $g$ is not used as input. The inputs are not modified. The output array $g$ must have room for $\min(\mathit{gn}, \mathit{xn}_i)$ limbs, the minimum taken over the nonzero inputs, and must not overlap the values.