diff --git a/include/wx/cpp.h b/include/wx/cpp.h
index b5ce014e4d..dd40696d83 100644
--- a/include/wx/cpp.h
+++ b/include/wx/cpp.h
@@ -130,13 +130,13 @@
     /* Any C99 or C++11 compiler should have them. */
     #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
         (defined(__cplusplus) && __cplusplus >= 201103L)
-        #define HAVE_VARIADIC_MACROS
+        #define HAVE_VARIADIC_MACROS 1
     #elif wxCHECK_GCC_VERSION(3,0)
-        #define HAVE_VARIADIC_MACROS
+        #define HAVE_VARIADIC_MACROS 1
     #elif wxCHECK_VISUALC_VERSION(8)
-        #define HAVE_VARIADIC_MACROS
+        #define HAVE_VARIADIC_MACROS 1
     #elif wxCHECK_WATCOM_VERSION(1,2)
-        #define HAVE_VARIADIC_MACROS
+        #define HAVE_VARIADIC_MACROS 1
     #endif
 #endif /* !HAVE_VARIADIC_MACROS */