winex11: Add infrastructure for managing the extra data of generic extension events.
diff --git a/configure b/configure
index 76ecd55..8e8d044 100755
--- a/configure
+++ b/configure
@@ -8733,6 +8733,18 @@
 
 
 fi
+ac_fn_c_check_member "$LINENO" "XEvent" "xcookie" "ac_cv_member_XEvent_xcookie" "#ifdef HAVE_X11_XLIB_H
+#include <X11/Xlib.h>
+#endif
+"
+if test "x$ac_cv_member_XEvent_xcookie" = x""yes; then :
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_XEVENT_XCOOKIE 1
+_ACEOF
+
+
+fi