Defines starting with `n' in bsd/kern

• NA bsd/kern/tty.c:170
• NL bsd/kern/tty.c:171
• NO bsd/kern/tty.c:172
• NPTY bsd/kern/tty_pty.c:135
• NSNP bsd/kern/tty.c:94
• NTBS bsd/kern/tty_tb.c:122