Differentiate between Windows Ink (pen) and regular touch input

src/video/windows/SDL_windowsevents.c

@@ -1339,7 +1339,7 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
                     /* TODO: Can we use GetRawInputDeviceInfo and HID info to
                        determine if this is a direct or indirect touch device?
                      */
-                    if (SDL_AddTouch(touchId, SDL_TOUCH_DEVICE_DIRECT, "") < 0) {
+                    if (SDL_AddTouch(touchId, SDL_TOUCH_DEVICE_DIRECT, (input->dwFlags & TOUCHEVENTF_PEN) == TOUCHEVENTF_PEN ? "pen" : "touch") < 0) {
                         continue;
                     }