Hello,

This came from an thread between myself and MarkK (I can't find the url).

The current native code constructs its target vector using a convoluted 
combination of #ifdefs and global functions.

This patch replaces all that with what is effectively a runtime 
inheritance structure:

	inf-ptrace is-a inf-child is-a target

I've updated/tested NetBSD/PPC, with a tweak to nbsdppc-nat. that 
further extends the above with:

	nbsdppc-nat is-a inf-ptrace

there were no regressions.

The intent is for all natives to eventually migrate to this.

Comments?

Right now I'm more interested in high-level stuff - the idea and the 
strategy.  I'm sure the implementation will evolve as more natives come 
on board, and as I eliminate a few remaining globals.

I'll leave this for a week,

Andrew