Method alignment

dlib/external/pybind11/include/pybind11/numpy.h:741–741

/// Alignment of the data type
#ifdef PYBIND11_NUMPY_1_ONLY
    int alignment() const { return detail::array_descriptor_proxy(m_ptr)->alignment; }
#else
    ssize_t alignment() const {
        if (detail::npy_api::get().PyArray_RUNTIME_VERSION_ < 0x12) {