Give input focus to globally active clients

This technically violates the ICCCM, but the alternative is not much
better: these windows *will* have focus in the GUI qube, so not giving
them focus on the agent side will cause the X state to no longer be the
same on both sides.  Worse, such clients might not be expecting to lose
focus without warning.  Explicitly taking focus away from them might
help.

This is based on a similar commit in wlroots.

gui-agent/vmside.c

@@ -1812,7 +1812,7 @@ static void handle_focus(Ghandles * g, XID winid)
         }
 
         // Give input focus only to window that set the input hint
-        if (input_hint)
+        if (input_hint || take_focus)
             XSetInputFocus(g->display, winid, RevertToParent, g->time);
 
         // Do not send take focus if the window doesn't support it
@@ -1830,7 +1830,7 @@ static void handle_focus(Ghandles * g, XID winid)
             fprintf(stderr, "WARNING handle_focus: Window 0x%x data not initialized", (int)winid);
             input_hint = True;
         }
-        if (input_hint)
+        if (input_hint || take_focus)
             XSetInputFocus(g->display, None, RevertToParent, g->time);
 
         if (g->log_level > 1)