This is a great question - and one I've tried to find an answer to myself. Sadly, it looks like there is no "quick fix". Currently, Apple considers Constraint-based layout Opt-in - even naming a section of the UIView Class Reference:
Opting in to Constraint-Based Layout
But that Opt-in is not global. I presume this is because not everything looks good if you just turn Springs & Struts into Constraints. Some UI elements break, or you would get a ton of unsatisfiable constraints errors.
I can think of one possible solution - I have not tried it myself, but you could make a category on UIView that sets all UIView objects to return NO for - (BOOL)translatesAutoresizingMaskIntoConstraints. While I do not know what this would break, it would globally set translatesAutoresizingMaskIntoConstraints to NO.
Here is a good introduction to Categories if you want to learn more about them!