Defines starting with `b' in osfmk/kern

• BASEPRI_KERNEL osfmk/kern/sched.h:103
• BASEPRI_SERVER osfmk/kern/sched.h:105
• BASEPRI_SYSTEM osfmk/kern/sched.h:104
• BASEPRI_USER osfmk/kern/sched.h:106
• base_size osfmk/kern/syscall_emulation.c:76