diff --git a/Directory.Build.targets b/Directory.Build.targets
index bf296bb2..10fa1262 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -82,6 +82,7 @@
$(DefineConstants);SUPPORTS_MULTIPLE_VALUES_IN_QUERYHELPERS
+ $(DefineConstants);SUPPORTS_HTTP_CLIENT_DEFAULT_REQUEST_VERSION_POLICY