--- a/source.list	Wed May 09 20:22:49 2007 +0000
+++ b/source.list	Thu May 10 15:07:16 2007 +0000
@@ -304,6 +304,7 @@
 # AI Core
 ai/ai.cpp
 ai/ai.h
+#if NO_THREADS
 ai/ai_factory.hpp
 ai/ai_squirrel.cpp
 ai/ai_squirrel.hpp
@@ -369,6 +370,7 @@
 ai/api/ai_vehicle.cpp
 ai/api/ai_vehiclelist.cpp
 ai/api/ai_vehiclelist_valuator.cpp
+#end
 
 # NewGRF
 newgrf.cpp