Bug #7403 error "Forcing close of thread 1 user: 'xxx'"

The problem was that on Windows, the socket was in a blocking state 
trying to read.  Setting killed=1 is not enough to break the 
socket out of it's read loop.   You have to cancel the read request
or close the socket (which close_connection does).

sql/mysqld.cc

@@ -657,7 +657,7 @@ static void close_connections(void)
   {
     DBUG_PRINT("quit",("Informing thread %ld that it's time to die",
 		       tmp->thread_id));
-    tmp->killed=1;
+    close_connection(tmp, 0, 1);  
     if (tmp->mysys_var)
     {
       tmp->mysys_var->abort=1;