MERGE 4.07

* This fix cures the weird 'ifaceBinds' error that
  Sven and George tripped over.  It was quite obscure!

  Basically, there was a top level binding
	f = x
  lying around, which CoreToStg didn't like.  Why hadn't
  it been substituted away?  Because it had a NOINLINE
  pragma.  Why did it have a NOINLINE pragma?  Because
  it's an always-diverging function, so we never want to
  inline it.