Defines starting with `n' in bsd/kern

• NA bsd/kern/tty.c:168
• NL bsd/kern/tty.c:169
• NO bsd/kern/tty.c:170
• NPTY bsd/kern/tty_pty.c:129
• NSNP bsd/kern/tty.c:90
• NTBS bsd/kern/tty_tb.c:91