Fixed compiler warning about redundant declaration.

SDL_RecordGesture() is already in the gesture header with additional specifiers.

src/events/SDL_gesture_c.h

@@ -27,8 +27,6 @@ extern int SDL_GestureAddTouch(SDL_TouchID touchId);
 
 extern void SDL_GestureProcessEvent(SDL_Event* event);
 
-extern int SDL_RecordGesture(SDL_TouchID touchId);
-
 #endif /* SDL_gesture_c_h_ */
 
 /* vi: set ts=4 sw=4 expandtab: */