Philippe Gorley authored Nov 09, 2016 and Philippe Gorley committed Nov 22, 2016

Correctly wraps video preferences and hardware acceleration
in ifdef preprocessor statements (RING_VIDEO and RING_ACCEL,
respectively). This fixes cases where Ring would not compile without
video or video acceleration. Video acceleration is now dependant on
the presence of video (--disable-video disables acceleration).

Change-Id: I087cc1dc794d0f19daa68cdaec09e126542147f9