Log Message:
SDL2: update to 2.0.16

General:

    Added SDL_FlashWindow() to get a user’s attention
    Added SDL_GetAudioDeviceSpec() to get the preferred audio format of a device
    Added SDL_SetWindowAlwaysOnTop() to dynamically change the \ 
SDL_WINDOW_ALWAYS_ON_TOP flag for a window
    Added SDL_SetWindowKeyboardGrab() to support grabbing the keyboard \ 
independently of the mouse
    Added SDL_SoftStretchLinear() to do bilinear scaling between 32-bit software \ 
surfaces
    Added SDL_UpdateNVTexture() to update streaming NV12/21 textures
    Added SDL_GameControllerSendEffect() and SDL_JoystickSendEffect() to allow \ 
sending custom trigger effects to the DualSense controller
    Added SDL_GameControllerGetSensorDataRate() to get the sensor data rate for \ 
PlayStation and Nintendo Switch controllers
    Added support for the Amazon Luna game controller
    Added rumble support for the Google Stadia controller using the HIDAPI driver
    Added SDL_GameControllerType constants for the Amazon Luna and Google Stadia \ 
controllers
    Added analog rumble for Nintendo Switch Pro controllers using the HIDAPI driver
    Reduced CPU usage when using SDL_WaitEvent() and SDL_WaitEventTimeout()