render: Added SDL_RenderFlush().

src/dynapi/SDL_dynapi_overrides.h

@@ -696,3 +696,4 @@
 #define SDL_SensorUpdate SDL_SensorUpdate_REAL
 #define SDL_IsTablet SDL_IsTablet_REAL
 #define SDL_GetDisplayOrientation SDL_GetDisplayOrientation_REAL
+#define SDL_RenderFlush SDL_RenderFlush_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -738,3 +738,4 @@ SDL_DYNAPI_PROC(void,SDL_SensorClose,(SDL_Sensor *a),(a),)
 SDL_DYNAPI_PROC(void,SDL_SensorUpdate,(void),(),)
 SDL_DYNAPI_PROC(SDL_bool,SDL_IsTablet,(void),(),return)
 SDL_DYNAPI_PROC(SDL_DisplayOrientation,SDL_GetDisplayOrientation,(int a),(a),return)
+SDL_DYNAPI_PROC(int,SDL_RenderFlush,(SDL_Renderer *a),(a),return)