Variables starting with `b' in osfmk/default_pager

• backing_store_list osfmk/default_pager/default_pager_internal.h:317
• bs_clsize osfmk/default_pager/default_pager_types.h:70
• bsl_lock osfmk/default_pager/default_pager_internal.h:316
• bs_pages_out_fail osfmk/default_pager/default_pager_internal.h:296