diff --git a/include/wx/wxcrtvararg.h b/include/wx/wxcrtvararg.h
index 85b18d6135..5516c5a083 100644
--- a/include/wx/wxcrtvararg.h
+++ b/include/wx/wxcrtvararg.h
@@ -52,6 +52,9 @@
     int snprintf(char *str, size_t size, const char *format, ...);
 #endif /* !HAVE_SNPRINTF_DECL */
 
+#ifdef __WATCOMC__
+    #define HAVE_VSSCANF_DECL
+#endif
 #if defined(HAVE_VSSCANF) && !defined(HAVE_VSSCANF_DECL)
 #ifdef __cplusplus
     extern "C"