(svn r2908) If threaded saving fails or does not happen, sending subsequent messages might hang ottd. So don't send them :)

saveload.c

@@ -1283,6 +1283,8 @@ void SaveFileError(void)
 	SaveFileDone();
 }
 
+static Thread* save_thread;
+
 /** We have written the whole game into memory, _save_pool, now find
  * and appropiate compressor and start writing to file.
  */
@@ -1294,7 +1296,7 @@ static void* SaveFileToDisk(void *arg)
 	static byte *tmp = NULL;
 	uint32 hdr[2];
 
-	OTTD_SendThreadMessage(MSG_OTTD_SAVETHREAD_START);
+	if (save_thread != NULL) OTTD_SendThreadMessage(MSG_OTTD_SAVETHREAD_START);
 
 	tmp = _sl.buf;
 
@@ -1341,13 +1343,10 @@ static void* SaveFileToDisk(void *arg)
 	GetSavegameFormat("memory")->uninit_write(); // clean the memorypool
 	fclose(_sl.fh);
 
-	OTTD_SendThreadMessage(MSG_OTTD_SAVETHREAD_DONE);
+	if (save_thread != NULL) OTTD_SendThreadMessage(MSG_OTTD_SAVETHREAD_DONE);
 	return NULL;
 }
 
-
-static Thread* save_thread;
-
 void WaitTillSaved(void)
 {
 	OTTDJoinThread(save_thread);