Implement mach headers

[gnzlbg]

Note: this crate exposes the user space Mach API, that is, the one that gets linked via libSystem and/or libsystem_kernel. It's headers are in /usr/include/mach.

This approximately summarizes the current implementation:

• boolean.h
• bootstrap.h
• (maybe incomplete) clock.h
• (maybe incomplete) clock_priv.h
• (maybe incomplete) clock_reply.h
• (maybe incomplete) clock_types.h
• (maybe incomplete) dyld_kernel.h
• (maybe incomplete) error.h
• (maybe incomplete) exc.h
• exception.h
• (maybe incomplete) exception_types.h
• host_info.h
• host_notify.h
• host_priv.h
• host_reboot.h
• host_security.h
• host_special_ports.h
• (maybe incomplete) kern_return.h
• kmod.h
• lock_set.h
• mach.h
• mach_error.h
• mach_host.h
• mach_init.h
• mach_interface.h
• mach_param.h
• (maybe incomplete) mach_port.h
• mach_syscalls.h
• mach_time.h
• (maybe incomplete) mach_traps.h
• (maybe incomplete) mach_types.h
• mach_vm.h
• mach_voucher.h
• mach_voucher_types.h
• machine.h
• (maybe incomplete) memory_object_types.h
• (maybe incomplete) message.h
• mig.h
• mig_errors.h
• mig_strncpy_zerofill_support.h
• mig_voucher_support.h
• ndr.h
• notify.h
• policy.h
• (maybe incomplete) port.h
• port_obj.h
• processor.h
• processor_info.h
• processor_set.h
• rpc.h
• sdt.h
• semaphore.h
• shared_memory_server.h
• shared_region.h
• std_types.h
• sync.h
• sync_policy.h
• (maybe incomplete) task.h
• (maybe incomplete) task_info.h
• task_inspect.h
• task_policy.h
• task_special_ports.h
• (maybe incomplete) thread_act.h
• thread_info.h
• thread_policy.h
• thread_special_ports.h
• thread_state.h
• (maybe incomplete) thread_status.h
• thread_switch.h
• time_value.h
• (maybe incomplete) vm_attributes.h
• (maybe incomplete) vm_behavior.h
• (maybe incomplete) vm_inherit.h
• vm_map.h
• (maybe incomplete) vm_page_size.h
• (maybe incomplete) vm_param.h
• (maybe incomplete) vm_prot.h
• (maybe incomplete) vm_purgable.h
• (maybe incomplete) vm_region.h
• (maybe incomplete) vm_statistics.h
• (maybe incomplete) vm_sync.h
• vm_task.h
• (maybe incomplete) vm_types.h