illumos build should not depend upon 'extras' pkg repository
The extras repository is currently required to build onnv, and thus illumos.
The extras repository contains non-redistributable components that cannot be
distributed by anyone except Oracle (or, presumably, some licensees).
It is in the interests of illumos to remove hard dependencies on these packages.
At present, these dependencies are:
- wbem (used by cmd/wbem, libfsmgt, and dhcpmgr)
I've done various bits of hacking in this basic direction, so I'm taking this for
right now, though I may not keep it.