Fixed compile warnings

include/SDL_clipboard.h

@@ -53,14 +53,14 @@ extern DECLSPEC int SDLCALL SDL_SetClipboardText(const char *text);
  *
  * \sa SDL_SetClipboardText()
  */
-extern DECLSPEC char * SDLCALL SDL_GetClipboardText();
+extern DECLSPEC char * SDLCALL SDL_GetClipboardText(void);
 
 /**
  * \brief Returns whether the clipboard has text
  *
  * \sa SDL_GetClipboardText()
  */
-extern DECLSPEC SDL_bool SDLCALL SDL_HasClipboardText();
+extern DECLSPEC SDL_bool SDLCALL SDL_HasClipboardText(void);
 
 
 /* Ends C function definitions when using C++ */

src/events/SDL_clipboardevents.c

@@ -29,7 +29,7 @@
 
 
 int
-SDL_SendClipboardUpdate()
+SDL_SendClipboardUpdate(void)
 {
     int posted;
 

src/events/SDL_clipboardevents_c.h

@@ -24,7 +24,7 @@
 #ifndef _SDL_clipboardevents_c_h
 #define _SDL_clipboardevents_c_h
 
-extern int SDL_SendClipboardUpdate();
+extern int SDL_SendClipboardUpdate(void);
 
 #endif /* _SDL_clipboardevents_c_h */
 

src/video/SDL_clipboard.c

@@ -42,7 +42,7 @@ SDL_SetClipboardText(const char *text)
 }
 
 char *
-SDL_GetClipboardText()
+SDL_GetClipboardText(void)
 {
     SDL_VideoDevice *_this = SDL_GetVideoDevice();
 
@@ -58,7 +58,7 @@ SDL_GetClipboardText()
 }
 
 SDL_bool
-SDL_HasClipboardText()
+SDL_HasClipboardText(void)
 {
     SDL_VideoDevice *_this = SDL_GetVideoDevice();