sdl: fix mouseclick operations in "--nogui" mode (ie: zapper)

src/drivers/sdl/input.cpp

@@ -720,6 +720,8 @@ GetMouseData(uint32 (&d)[3])
     t = SDL_GetMouseState(&x, &y);
     SDL_Event event;
 #ifdef _GTK
+    if(noGui == 0)
+    {
       // don't ask for gtk mouse info when in fullscreen
       // we can use sdl directly in fullscreen
       int fullscreen = 0;
@@ -730,6 +732,7 @@ GetMouseData(uint32 (&d)[3])
         y=GtkMouseData[1];
         t=GtkMouseData[2];
       }
+    }
 #endif
 
     d[2] = 0;