dep/msvc: Update SDL2 to 2.0.16

dep/msvc/sdl2/include/SDL_clipboard.h

@@ -1,6 +1,6 @@
 /*
   Simple DirectMedia Layer
-  Copyright (C) 1997-2019 Sam Lantinga <slouken@libsdl.org>
+  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
 
   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
@@ -39,23 +39,41 @@ extern "C" {
 /* Function prototypes */
 
 /**
- * \brief Put UTF-8 text into the clipboard
+ * Put UTF-8 text into the clipboard.
  *
- * \sa SDL_GetClipboardText()
+ * \param text the text to store in the clipboard
+ * \returns 0 on success or a negative error code on failure; call
+ *          SDL_GetError() for more information.
+ *
+ * \sa SDL_GetClipboardText
+ * \sa SDL_HasClipboardText
  */
 extern DECLSPEC int SDLCALL SDL_SetClipboardText(const char *text);
 
 /**
- * \brief Get UTF-8 text from the clipboard, which must be freed with SDL_free()
+ * Get UTF-8 text from the clipboard, which must be freed with SDL_free().
  *
- * \sa SDL_SetClipboardText()
+ * This functions returns NULL if there was not enough memory left for a copy
+ * of the clipboard's content.
+ *
+ * \returns the clipboard text on success or NULL on failure; call
+ *          SDL_GetError() for more information. Caller must call SDL_free()
+ *          on the returned pointer when done with it.
+ *
+ * \sa SDL_HasClipboardText
+ * \sa SDL_SetClipboardText
  */
 extern DECLSPEC char * SDLCALL SDL_GetClipboardText(void);
 
 /**
- * \brief Returns a flag indicating whether the clipboard exists and contains a text string that is non-empty
+ * Query whether the clipboard exists and contains a non-empty text string.
  *
- * \sa SDL_GetClipboardText()
+ * \returns SDL_TRUE if the clipboard has text, or SDL_FALSE if it does not.
+ *
+ * \since This function is available since SDL 2.0.0.
+ *
+ * \sa SDL_GetClipboardText
+ * \sa SDL_SetClipboardText
  */
 extern DECLSPEC SDL_bool SDLCALL SDL_HasClipboardText(void);