Date#to_time

static VALUE
date_to_time(VALUE self)
{
    VALUE t;

    get_d1a(self);

    if (m_julian_p(adat)) {
        VALUE g = d_lite_gregorian(self);
        get_d1b(g);
        adat = bdat;
        self = g;
    }

    t = f_local3(rb_cTime,
        m_real_year(adat),
        INT2FIX(m_mon(adat)),
        INT2FIX(m_mday(adat)));
    RB_GC_GUARD(self); /* may be the converted gregorian */
    return t;
}