diff --git a/build/jam/ArchitectureRules b/build/jam/ArchitectureRules
index 116dca2bfb..ccff82bd49 100644
--- a/build/jam/ArchitectureRules
+++ b/build/jam/ArchitectureRules
@@ -659,6 +659,7 @@ rule ArchitectureSetupWarnings architecture
 	EnableWerror src system boot ;
 	EnableWerror src system kernel ;
 	EnableWerror src system libroot add-ons ;
+	EnableWerror src system libroot os ;
 	EnableWerror src system libroot posix locale ;
 	EnableWerror src system libroot posix wchar ;
 	EnableWerror src system runtime_loader ;