OK, so at least for 3.7, we'll replace the SystemError with a recursive import of the missing parent package, just as we'd expect to see with an absolute import.

I'm classing this as "Won't fix" for the native import system in 2.7 - folks wanting the fix there will need to switch to using importlib2 (assuming that gets updated to include the fix at some point).

That leaves 3.5 and 3.6, and I'd suggest we defer making a decision about whether or not to backport the fix to the maintenance branches until after we see how complex the patch for 3.7 ends up being.