Fixes for DirectFB
This backend causes SDL to crash when it initializes with haptic support (SDL uses udev, which isn't available/working in initfs for directfb for reasons I didn't dig into further).
!112 (merged) also introduced a regression with DirectFB where the keyboard does not render.
This MR works around both issues by adding a helper to detect when the app is using DirectFB, and disabling the relevant features.
Edited by Administrator