This prevents conflicts with hidapi linked with applications, as well as allowing applications to make use of HIDAPI on Android and other platforms that might not normally have an implementation available.
meyraud705
Dualshock4 on bluetooth need 78 bytes for the rumble data while SDL_HIDAPI_RumbleRequest can only hold 64 bytes.
'volatile' is not meant for thread synchronization.
The list of rumble request could grow infinitely if user call SDL_JoystickRumble too much. The documentation says "Each call to this function cancels any previous rumble effect", so overwriting pending request seem like a good idea.
