Defines starting with `c' in kern

• CC kern/tty.c:90
• CCLASSMASK kern/tty.c:81
• CCPU_SHIFT kern/kern_synch.c:147
• COMP_T_EXP_BASE_BITS kern/kern_acct.c:104
• COMP_T_FRACT_BITS kern/kern_acct.c:102
• CR kern/tty.c:95