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       Fix a long-standing indirection-zapping bug
	-----------------------------------------

	Merge to STABLE

Up to now we zap indirections as part of the occurence analyser.
But this is bogus.  The indirection zapper does the following:

	x_local = <expression>
	...bindings...
	x_exported = x_local

where x_exported is exported, and x_local is not, then we
replace it with this:

	x_exported = <expression>
	x_local = x_exported
	...bindings...

But this is plain wrong if x_exported has a RULE that mentions
something (f, say) in ...bindings.., because 'f' will then die.

After hacking a few solutions, I've eventually simply made the indirection
zapping into a separate pass (which is cleaner anyway), which wraps the
entire program back into a single Rec if the bad thing can happen.

On the way I've made indirection-zapping work in Recs too, which wasn't the
case before.

* Move the zapper from OccurAnal into SimplCore
* Tidy up the printing of pragmas (PprCore and friends)
* Add a new function Rules.addRules
* Merge rules in the indirection zapper (previously one set was discarded)