The problem here was the logic that detects SDL in the main CMakeLists.txt
is not the same as it is in DolphinWX/CmakeLists.txt to set libraries. When
using SDL from Externals it failed at link time because -lSDL was never set.
This fixes the problem by using the same condition logic to set the libs
as used when detecting SDL in the first place.
This adds support for drivers supporting sine, square and triangle
periodic haptic effects. This allows rumble to work on devices/drivers
supporting these effects, such as an xbox controller using the xpad
driver under Linux.
Dolphin code already builds against SDL2 but the build system never
checks for SDL2, which is the what latest SDL is called now. SDL2
replaces SDL 1.3. This allows Dolphin to be build against SDL2, which
activates certain new features such as the haptic interface.
Scott Moreau