fix includes; new proc struct; rm *_NULL

fix includes; new proc struct; rm *_NULL

SCCS-vsn: sys/vm/device_pager.c 7.2
SCCS-vsn: sys/vm/pmap.h 7.2
SCCS-vsn: sys/vm/swap_pager.c 7.3
SCCS-vsn: sys/vm/vm_fault.c 7.5
SCCS-vsn: sys/vm/vm_init.c 7.2
SCCS-vsn: sys/vm/vm_kern.c 7.2
SCCS-vsn: sys/vm/vm_map.h 7.2
SCCS-vsn: sys/vm/vm_meter.c 7.11
SCCS-vsn: sys/vm/vm_object.c 7.2
SCCS-vsn: sys/vm/vm_object.h 7.2
SCCS-vsn: sys/vm/vm_page.c 7.2
SCCS-vsn: sys/vm/vm_page.h 7.2
SCCS-vsn: sys/vm/vm_pageout.c 7.2
SCCS-vsn: sys/vm/vm_pageout.h 7.2
SCCS-vsn: sys/vm/vm_pager.c 7.2
SCCS-vsn: sys/vm/vm_pager.h 7.2
SCCS-vsn: sys/vm/vm_unix.c 7.2
SCCS-vsn: sys/vm/vm_user.c 7.2
SCCS-vsn: sys/vm/vnode_pager.c 7.5