iv_wait: Use 'union wait' on Tru64.
iv_wait: Use 'union wait' on Tru64.

On Tru64, the second ('status') argument to wait4() is not an int *,
but a union wait * (which contains the actual exit status code).

Signed-off-by: Lennert Buytenhek <8858498612e3a522354216649776e3032dcb7e5b@wantstofly.org>

buytenh/ivykis,buytenh/ivykis