diff --git a/project.xml b/project.xml
index ef7c2bc0..d9208b58 100644
--- a/project.xml
+++ b/project.xml
@@ -219,15 +219,18 @@
 
 	<haxedef name="HXCPP_M32" if="32bit"/>
 	<haxedef name="HXCPP_DEBUG_LINK" if="debug"/>
+	<haxedef name="HXCPP_CPP20"/>
 	<!--<haxedef name="HXCPP_CLANG"/>-->
 	<haxedef name="HXCPP_MSVC"/>
-	<!--<haxedef name="HXCPP_GC_BIG_BLOCKS"/>-->
+	<haxedef name="HXCPP_GC_BIG_BLOCKS"/>
+	<haxedef name="HXCPP_GC_GENERATIONAL"/>
+	<haxedef name="HXCPP_GC_DYNAMIC_SIZE"/>
 	<haxedef name="HXCPP_CHECK_POINTER"/>
 	<haxedef name="HXCPP_STACK_LINE"/>
 	<haxedef name="HXCPP_STACK_TRACE"/>
 	<haxedef name="HXCPP_CATCH_SEGV"/>
-	<!--<haxedef name="HXCPP_ALIGN_ALLOC"/>-->
-	<!--<haxedef name="HXCPP_DEBUG_LINK"/>-->
+	<haxedef name="HXCPP_FAST_LINK"/>
+	<!--<haxedef name="HXCPP_ALIGN_ALLOC"/>--> <!--hxcpp.h(71): warning C4005: 'HXCPP_ALIGN_ALLOC': macro redefinition-->
 
 	<haxedef name="analyzer-optimize" unless="debug"/>
 </project>