diff --git a/Common.props b/Common.props
index a2de0c2fa4..1dda6800e9 100644
--- a/Common.props
+++ b/Common.props
@@ -19,4 +19,7 @@
 		<DefineConstants>TRACE</DefineConstants>
 		<Optimize>true</Optimize>
 	</PropertyGroup>
+	<PropertyGroup Condition=" '$(MachineExtraCompilationFlag)' != '' ">
+		<DefineConstants>$(DefineConstants);$(MachineExtraCompilationFlag)</DefineConstants>
+	</PropertyGroup>
 </Project>