Differentiate between Windows Ink (pen) and regular touch input

SDL2 backport of https://github.com/libsdl-org/SDL/pull/5926

src/video/windows/SDL_windowsevents.c

@@ -99,6 +99,9 @@
 #ifndef WM_GETDPISCALEDSIZE
 #define WM_GETDPISCALEDSIZE 0x02E4
 #endif
+#ifndef TOUCHEVENTF_PEN
+#define TOUCHEVENTF_PEN 0x0040
+#endif
 
 #ifndef IS_HIGH_SURROGATE
 #define IS_HIGH_SURROGATE(x) (((x) >= 0xd800) && ((x) <= 0xdbff))
@@ -1396,7 +1399,7 @@ 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;
                     }