ui/sdl2: Allow host to power down screen

By default, SDL disables the screen saver which prevents the host from powering
down the screen even if the screen is locked. This results in draining the
battery needlessly when the host isn't connected to a wall charger. Fix that by
enabling the screen saver.

Signed-off-by: Bernhard Beschow <[email protected]>
Acked-by: Marc-André Lureau <[email protected]>
Message-ID: <[email protected]>
(cherry picked from commit 2e701e6)
Signed-off-by: Michael Tokarev <[email protected]>

Author: shentok

ui/sdl2.c

@@ -874,6 +874,7 @@ static void sdl2_display_init(DisplayState *ds, DisplayOptions *o)
     SDL_SetHint(SDL_HINT_ALLOW_ALT_TAB_WHILE_GRABBED, "0");
 #endif
     SDL_SetHint(SDL_HINT_WINDOWS_NO_CLOSE_ON_ALT_F4, "1");
+    SDL_EnableScreenSaver();
     memset(&info, 0, sizeof(info));
     SDL_VERSION(&info.version);