cocoa: Make keyboard grab function return an int

src/video/cocoa/SDL_cocoakeyboard.h

@@ -31,6 +31,6 @@ extern void Cocoa_StartTextInput(SDL_VideoDevice *_this);
 extern void Cocoa_StopTextInput(SDL_VideoDevice *_this);
 extern int Cocoa_SetTextInputRect(SDL_VideoDevice *_this, const SDL_Rect *rect);
 
-extern void Cocoa_SetWindowKeyboardGrab(SDL_VideoDevice *_this, SDL_Window *window, SDL_bool grabbed);
+extern int Cocoa_SetWindowKeyboardGrab(SDL_VideoDevice *_this, SDL_Window *window, SDL_bool grabbed);
 
 #endif /* SDL_cocoakeyboard_h_ */

src/video/cocoa/SDL_cocoakeyboard.m

@@ -467,11 +467,12 @@ typedef enum
 extern CGSConnection _CGSDefaultConnection(void);
 extern CGError CGSSetGlobalHotKeyOperatingMode(CGSConnection connection, CGSGlobalHotKeyOperatingMode mode);
 
-void Cocoa_SetWindowKeyboardGrab(SDL_VideoDevice *_this, SDL_Window *window, SDL_bool grabbed)
+int Cocoa_SetWindowKeyboardGrab(SDL_VideoDevice *_this, SDL_Window *window, SDL_bool grabbed)
 {
 #ifdef SDL_MAC_NO_SANDBOX
     CGSSetGlobalHotKeyOperatingMode(_CGSDefaultConnection(), grabbed ? CGSGlobalHotKeyDisable : CGSGlobalHotKeyEnable);
 #endif
+    return 0;
 }
 
 #endif /* SDL_VIDEO_DRIVER_COCOA */