This is xnu-8019. See this file in:
Directory listing for xnu-8019//libsyscall/mach
.gitignore
abort.h
add_attributes_to_mig.txt
clock.defs
clock_priv.defs
clock_reply.defs
clock_sleep.c
err_iokit.sub
err_ipc.sub
err_kern.sub
err_libkern.sub
err_mach_ipc.sub
err_server.sub
err_us.sub
error_codes.c
errorlib.h
exc.defs
exc_catcher.c
exc_catcher.h
exc_catcher_state.c
exc_catcher_state_identity.c
externs.h
fprintf_stderr.c
host.c
host_priv.defs
host_security.defs
ledger.defs
lock_set.defs
mach/
mach_error.c
mach_error_string.c
mach_eventlink.c
mach_eventlink.defs
mach_host.defs
mach_init.c
mach_legacy.c
mach_msg.c
mach_port.c
mach_port.defs
mach_right.c
mach_traps.s
mach_vm.c
mach_vm.defs
mach_voucher.defs
memory_entry.defs
mig_allocate.c
mig_deallocate.c
mig_reply_port.c
mig_reply_setup.c
mig_strncpy.c
ms_thread_switch.c
notify.defs
panic.c
port_descriptions.c
port_obj.c
processor.defs
processor_set.defs
restartable.defs
semaphore.c
servers/
slot_name.c
stack_logging_internal.h
string.c
string.h
task.c
task.defs
thread_act.c
thread_act.defs
vm_map.defs