diff --git a/build/jam/BuildSetup b/build/jam/BuildSetup
index c1ce28828f..08bd75cd1c 100644
--- a/build/jam/BuildSetup
+++ b/build/jam/BuildSetup
@@ -1363,6 +1363,9 @@ if $(HAIKU_NO_WERROR) != 1 {
 	EnableWerror src preferences ;
 	EnableWerror src servers ;
 	EnableWerror src system kernel ;
+	EnableWerror src system libroot add-ons ;
+	EnableWerror src system libroot posix locale ;
+	EnableWerror src system libroot posix wchar ;
 	EnableWerror src system runtime_loader ;
 }