intel-virtual-output: Discard unwanted events from the mouse recorder

X always sends MappingNotify events (there is no way for the client
to ignore them). In particular, MappingNotify would be sent after a VT
switch, and this would knock out our ability to track the cursor..

Reported-by: Raul Dias <raul@dias.com.br>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75115
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

tools/virtual.c

@@ -2987,7 +2987,8 @@ int main(int argc, char **argv)
 		if (reconfigure && context_update(&ctx))
 			display_reset_damage(ctx.display);
 
-		XPending(ctx.record);
+		while (XPending(ctx.record)) /* discard all implicit events */
+			XNextEvent(ctx.record, &e);
 
 		if (ctx.timer_active && read(ctx.timer, &count, sizeof(count)) > 0) {
 			struct clone *clone;