Macros starting with `b' in sys

• B_ADAPTOR sys/reboot.h:68
• B_CONTROLLER sys/reboot.h:71
• B_PARTITION sys/reboot.h:77
• btokmemx sys/malloc.h:256
• btokup sys/malloc.h:257
• B_TYPE sys/reboot.h:80
• BUCKETINDX sys/malloc.h:219
• B_UNIT sys/reboot.h:74