diff --git a/include/wx/osx/config_xcode.h b/include/wx/osx/config_xcode.h
index a8257a636b..03311e0396 100644
--- a/include/wx/osx/config_xcode.h
+++ b/include/wx/osx/config_xcode.h
@@ -13,7 +13,7 @@
 
 #define HAVE_SSIZE_T 1
 #define STDC_HEADERS 1
-#if __BIG_ENDIAN__
+#ifdef __BIG_ENDIAN__
 #define WORDS_BIGENDIAN 1
 #endif
 #define wxUSE_UNIX 1