MSTATUS
dot->m_flag |= MSTATUS;
mp->m_flag |= MSTATUS;
if (mp->m_flag & (MODIFY|MDELETED|MSTATUS))
mp->m_flag |= MSTATUS;
if (mp->m_flag & MSTATUS)
if (ishead && (mailp->m_flag & MSTATUS))
mp->m_flag |= MREAD|MSTATUS;
case MSTATUS: