Typedefs starting with `a' in osfmk/mach

• act_params_t osfmk/mach/rpc.h:174
• alarm_port_t osfmk/mach/mach_types.h:184
• alarm_t osfmk/mach/mach_types.h:122
• alarm_type_t osfmk/mach/clock_types.h:52