Defines starting with `u' in netccitt

• UA netccitt/hdlc.h:131
• UA_CONTROL netccitt/hdlc.h:102
• u_bb netccitt/llc_var.h:103
• UNUMBERED_CONTROL netccitt/llc_var.h:264
• u_pf netccitt/llc_var.h:105
• u_select netccitt/llc_var.h:106
• u_select_other netccitt/llc_var.h:104
• USES_AF_LINK_RTS netccitt/llc_var.h:586