internal/glfwwin: skip some functions for Xbox

Updates #2084

internal/glfwwin/win32window_windows.go

@@ -301,6 +301,10 @@ func (w *Window) enableCursor() error {
 }
 
 func (w *Window) cursorInContentArea() (bool, error) {
+	if microsoftgdk.IsXbox() {
+		return true, nil
+	}
+
 	pos, err := _GetCursorPos()
 	if err != nil {
 		return false, err
@@ -1442,6 +1446,9 @@ func (w *Window) platformDestroyWindow() error {
 }
 
 func (w *Window) platformSetWindowTitle(title string) error {
+	if microsoftgdk.IsXbox() {
+		return nil
+	}
 	return _SetWindowTextW(w.win32.handle, title)
 }
 
@@ -1829,6 +1836,9 @@ func (w *Window) platformSetWindowMonitor(monitor *Monitor, xpos, ypos, width, h
 }
 
 func (w *Window) platformWindowFocused() bool {
+	if microsoftgdk.IsXbox() {
+		return true
+	}
 	return w.win32.handle == _GetActiveWindow()
 }
 
@@ -1981,6 +1991,14 @@ func platformPollEvents() error {
 		}
 	}
 
+	var handle windows.HWND
+	if microsoftgdk.IsXbox() {
+		// Assume that there is always exactly one active window.
+		handle = _glfw.windows[0].win32.handle
+	} else {
+		handle = _GetActiveWindow()
+	}
+
 	// HACK: Release modifier keys that the system did not emit KEYUP for
 	// NOTE: Shift keys on Windows tend to "stick" when both are pressed as
 	//       no key up message is generated by the first key release
@@ -1988,7 +2006,7 @@ func platformPollEvents() error {
 	//       Other Win hotkeys are handled implicitly by _glfwInputWindowFocus
 	//       because they change the input focus
 	// NOTE: The other half of this is in the WM_*KEY* handler in windowProc
-	if handle := _GetActiveWindow(); handle != 0 {
+	if handle != 0 {
 		if window := handleToWindow[handle]; window != nil {
 			keys := [...]struct {
 				VK  int