Defines starting with `b' in bsd/kern

• b_cylinder bsd/kern/subr_disk.c:90
• BOTH bsd/kern/tty.c:2356
• BS bsd/kern/tty.c:165
• BSD_DUMMY_HOST bsd/kern/kern_mman.c:897
• _BSD_KERN_MACH_LOADER_H_ bsd/kern/mach_loader.h:35
• _BSD_KERN_PRELOAD_H_ bsd/kern/preload.h:23
• BUFSIZ bsd/kern/tty_pty.c:147