diff --git a/reactos/ReactOS.xml b/reactos/ReactOS.xml
index b5a53845f8e..ec887fb917d 100644
--- a/reactos/ReactOS.xml
+++ b/reactos/ReactOS.xml
@@ -10,6 +10,7 @@
 	<xi:include href="baseaddress.xml" />
 
 	<define name="_M_IX86" />
+	<define name="_X86_" />
 	<if property="MP" value="1">
 		<define name="CONFIG_SMP" value="1" />
 	</if>