As can be seen here and here, you need Orbis (now just PS4) SDK include files.
If I hex check libScePad_x64.dll
that comes with Dying Light demo, I can indeed see a Orbis_develop\libpad_for_win folder is mentioned.
Intriguingly, nearby libpad.dll
and libpadfilter.dll
sports a "2008 Sony Computer Entertainment Inc." copyright. I wonder if stuff was done for DS3 too?