[PATCH 0/1] MR9418: winex11.drv: use proper timestamp for X11 clipboard selection

[Jiajin Cui (＠jin-king1)]

1. Replace CurrentTime with actual server timestamp in clipboard
selection ownership
2. Add get_server_time function to retrieve current X11 server timestamp
by generating PropertyNotify event
3. Store selection timestamp globally for use in export_timestamp
function
4. Maintain original window event mask when getting server time

The previous implementation used CurrentTime (0) which can cause issues
with X11 clipboard handling. Using a proper server timestamp ensures
correct synchronization and prevents potential race conditions in
clipboard ownership transfers.

Signed-off-by: Jiajin Cui