sdl hide pointer when not in focus

diff -r e42ba25a7313 sdl.c
@@ -50,6 +50,7 @@
 static int guest_cursor = 0;
 static int guest_x, guest_y;
 static SDL_Cursor *guest_sprite = 0;
+static int mouse_active = SDL_ENABLE;
 
 static void sdl_update(DisplayState *ds, int x, int y, int w, int h)
 {

@@ -514,7 +515,8 @@
                         dz = 1;
                     }
 #endif
-                    sdl_send_mouse_event(0, 0, dz, bev->x, bev->y, buttonstate);
+                    if (mouse_active == SDL_ENABLE)
+                        sdl_send_mouse_event(0, 0, dz, bev->x, bev->y, buttonstate);
                 }
             }
             break;

@@ -522,6 +524,14 @@
             if (gui_grab && ev->active.state == SDL_APPINPUTFOCUS &&
                 !ev->active.gain && !gui_fullscreen_initial_grab) {
                 sdl_grab_end();
+            }
+            /* Send mouse pointer to oblivion on focus change */
+            if ((ev->active.state == SDL_APPINPUTFOCUS) ||
+                (ev->active.state == SDL_APPMOUSEFOCUS))
+            {
+                mouse_active = ev->active.gain;
+                if (mouse_active != SDL_ENABLE)
+                    kbd_mouse_event(0x7FFF, 0x7FFF, 0, 0);
             }
             if (ev->active.state & SDL_APPACTIVE) {
                 if (ev->active.gain) {