[RFC] Use target vector inheritance for GNU/Linux

[Andrew Cagney]

Daniel Jacobowitz wrote:
> One use of deprecated_child_ops was particularly thorny, so I updated the
> to_follow_fork method to take a struct target_ops and push the correct
> target.  I made to_follow_fork a non-inherited method, like to_xfer_partial.

This change is ok (you've even copied across the debug printing!), but 
commit it now so that it's not burried in amongst the other changes.

Andrew