diff --git a/osdep/main-fn-win.c b/osdep/main-fn-win.c
index dfccb4c910..cf2df57289 100644
--- a/osdep/main-fn-win.c
+++ b/osdep/main-fn-win.c
@@ -13,7 +13,7 @@
 #ifndef HEAP_OPTIMIZE_RESOURCES_CURRENT_VERSION
 
 #define HEAP_OPTIMIZE_RESOURCES_CURRENT_VERSION  1
-enum { HeapOptimizeResources = 3 };
+#define HeapOptimizeResources ((HEAP_INFORMATION_CLASS)3)
 
 struct HEAP_OPTIMIZE_RESOURCES_INFORMATION {
     DWORD Version;