diff --git a/src/AudacityHeaders.h b/src/AudacityHeaders.h
index dc75e0c17..176ed192b 100644
--- a/src/AudacityHeaders.h
+++ b/src/AudacityHeaders.h
@@ -75,7 +75,7 @@
 //    #include <wx/msw/msvcrt.h>      // redefines the NEW() operator
 //#endif
 
-#if __WXMSW__
+#ifdef __WXMSW__
 #ifdef _DEBUG
 #define _CRTDBG_MAP_ALLOC
 #include <crtdbg.h>