== DETAILS
After a bisect, the culprit was changing the gamepad interface from
returing a single button (bool) to multiple (int16).
The issue is that the Wii U gamepad (and presumably the Pro controller too)
have more than 16 buttons, which means some buttons get lost. Notably, L3 (18)
and R3 (17).
The solution: use int32 instead of int16.
I did a test build and confirmed that this change restores L3/R3 functionality
with the gamepad. Don't have a pro controller to test, but it should work too.
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