aff_pt_edwards_init_from_coords
ATTRIBUTE_WARN_UNUSED_RET int aff_pt_edwards_init_from_coords(aff_pt_edwards_t in,
ret = aff_pt_edwards_init_from_coords(out_edwards, edwards_crv, &zero, &one);
ret = aff_pt_edwards_init_from_coords(out, edwards_curve, &x, &y);