#include <mach/vm_task.h> not included by <mach/mach.h> — include it explicitly

mach/vm_task.h

* This file contains compatibilty wrapper header for things that are * generated from mach/vm_map.defs into mach/vm_map.h. * * This file will go away eventually - please switch.

This header declares nothing itself under the arm64 configuration; it groups the headers below.