(svn r5977) -Fix [FS#78]: never set I-am-a-thread bool to true IN the thread. Machines with

dualcore can be faster then you want, and therefor create 2 threads, while
  you made the bool to make sure there is never more then 1 thread of this type.

openttd.h

@@ -527,9 +527,9 @@ VARDEF byte _no_scroll;
  * the OTTD_SendThreadMessage() function. Actions to perform upon the message are handled
  * in the ProcessSentMessage() function */
 typedef enum ThreadMsgs {
-	MSG_OTTD_SAVETHREAD_START  = 1,
-	MSG_OTTD_SAVETHREAD_DONE   = 2,
-	MSG_OTTD_SAVETHREAD_ERROR  = 3,
+	MSG_OTTD_NO_MESSAGE,
+	MSG_OTTD_SAVETHREAD_DONE,
+	MSG_OTTD_SAVETHREAD_ERROR,
 } ThreadMsg;
 
 void OTTD_SendThreadMessage(ThreadMsg msg);