Add NetBSD Solaris compat code and reachover Makefiles. Most of code written
by Andrew Doran some of it by me.

This is still work in progress code. There are known issues. Zfs can panic
your system still. I will commit integration bits and needed kernel bits
later when we fix most obvious bugs. This code need some support from our
kernel which I will commit in a separate patch and therefore itnot work yet.

Issues:

1) Support for openat/fstatat syscalls.
2) getnewvnode locking against myself panic when reclaiming vnodes
3) Replace solaris taskq with our workqueue which doesn't need to alloc
anything during work.
4) Investigate problems with NO_WAIT allocations.

Oked by core@ and ad@.