Add child window id to its parent

I had accidentally removed this in b228ef13c4 and it broke all programs
that were using child windows :D

xbanan/Base.cpp

@@ -1400,6 +1400,8 @@ BAN::ErrorOr<void> handle_packet(Client& client_info, BAN::ConstByteSpan packet)
 			if (event_mask != 0)
 				TRY(object_it->value->object.get<Object::Window>().event_masks.insert(&client_info, event_mask));
 
+			TRY(parent_window.children.push_back(request.wid));
+
 			if (gui_window_ptr)
 			{
 				const WINDOW wid = request.wid;

xbanan/main.cpp

@@ -18,18 +18,19 @@
 #include <netinet/in.h>
 #endif
 
-static const xRectangle s_screen_bounds =
+static BAN::UniqPtr<LibGUI::Window> s_dummy_window =
 	[]() {
 		auto attributes = LibGUI::Window::default_attributes;
 		attributes.shown = false;
-		auto window = MUST(LibGUI::Window::create(0, 0, ""_sv, attributes));
-		return xRectangle {
+		return MUST(LibGUI::Window::create(0, 0, ""_sv, attributes));
+	}();
+
+static const xRectangle s_screen_bounds = {
 	.x = 0,
 	.y = 0,
-			.width = static_cast<CARD16>(window->width()),
-			.height = static_cast<CARD16>(window->height()),
-		};
-	}();
+	.width = static_cast<CARD16>(s_dummy_window->width()),
+	.height = static_cast<CARD16>(s_dummy_window->height()),
+};
 
 const xPixmapFormat g_formats[6] {
 	{
@@ -172,12 +173,25 @@ int main()
 		return 1;
 	}
 
+	{
 		epoll_event event { .events = EPOLLIN, .data = { .ptr = nullptr } };
 		if (epoll_ctl(g_epoll_fd, EPOLL_CTL_ADD, server_sock, &event) == -1)
 		{
 			perror("xbanan: epoll_ctl");
 			return 1;
 		}
+	}
+
+	{
+		epoll_event event { .events = EPOLLIN, .data = { .ptr = (void*)1 } };
+		if (epoll_ctl(g_epoll_fd, EPOLL_CTL_ADD, s_dummy_window->server_fd(), &event) == -1)
+		{
+			perror("xbanan: epoll_ctl");
+			return 1;
+		}
+
+		s_dummy_window->request_resize(1, 1);
+	}
 
 #define APPEND_ATOM(name) do { \
 			MUST(g_atoms_id_to_name.insert(name, #name##_sv.substring(3))); \
@@ -397,6 +411,12 @@ int main()
 				continue;
 			}
 
+			if (events[i].data.ptr == (void*)1)
+			{
+				s_dummy_window->poll_events();
+				continue;
+			}
+
 			auto it = g_epoll_thingies.find(events[i].data.fd);
 			if (it == g_epoll_thingies.end())
 				continue;