* netbsd/sys/sys/null.h: define NULL as (void *)0.  misuse of NULL as   integer value will be punished with compilation error.   sync with netbsd-current.
* netbsd/sys/sys/null.h: define NULL as (void *)0.  misuse of NULL as
  integer value will be punished with compilation error.
  sync with netbsd-current.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame