bump SDL2 includes to 2.0.14

Edward Rudd

2021-06-15 afe30686045992f09902c1d11347bee9cf87adbd

 include/SDL2/SDL_vulkan.h

@@ -153,7 +153,7 @@
 *  is smaller than the number of required extensions, \c SDL_FALSE will be
 *  returned instead of \c SDL_TRUE, to indicate that not all the required
 *  extensions were returned.
 * 
 *
 *  \note If \c window is not NULL, it will be checked against its creation
 *        flags to ensure that the Vulkan flag is present. This parameter
 *        will be removed in a future major release.
@@ -204,10 +204,9 @@
 *
 *  \sa SDL_Vulkan_CreateSurface()
 */
extern DECLSPEC SDL_bool SDLCALL SDL_Vulkan_GetInstanceExtensions(
                                          SDL_Window *window,
                                          unsigned int *pCount,
                                          const char **pNames);
extern DECLSPEC SDL_bool SDLCALL SDL_Vulkan_GetInstanceExtensions(SDL_Window *window,
                                                                  unsigned int *pCount,
                                                                  const char **pNames);

/**
 *  \brief Create a Vulkan rendering surface for a window.
@@ -238,10 +237,9 @@
 *
 *  \sa SDL_Vulkan_GetInstanceExtensions()
 */
extern DECLSPEC SDL_bool SDLCALL SDL_Vulkan_CreateSurface(
                                    SDL_Window *window,
                                    VkInstance instance,
                                    VkSurfaceKHR* surface);
extern DECLSPEC SDL_bool SDLCALL SDL_Vulkan_CreateSurface(SDL_Window *window,
                                                          VkInstance instance,
                                                          VkSurfaceKHR* surface);

/**
 *  \brief Get the size of a window's underlying drawable in pixels (for use