• Replace wait1() with a kern_wait() function that accepts the pid, options, status pointer and rusage pointer as arguments. It is up to the caller to copyout the status and rusage to userland if needed. This lets us axe the 'compat' argument and hide all that functionality in owait(), by the way. This also cleans up some locking in kern_wait() since it no longer has to drop locks around copyout() since all the copyout()'s are deferred.
• Convert owait(), wait4(), and the various ABI compat wait() syscalls to use kern_wait() rather than wait1() or wait4(). This removes a bit more stackgap usage.

Tested on: i386
Compiled on: i386, alpha, amd64