Defines starting with `s' in netccitt

• SABM netccitt/hdlc.h:128
• SABM_CONTROL netccitt/hdlc.h:101
• SABM_SENT netccitt/hdlc.h:117
• SENT_CALL netccitt/pk.h:156
• SENT_CLEAR netccitt/pk.h:159
• SIOCGIFCONF_X25 netccitt/x25.h:151
• SIOCSIFCONF_X25 netccitt/x25.h:150