diff --git a/Source/Additions/NSError+GNUstepBase.m b/Source/Additions/NSError+GNUstepBase.m
index bcceaf8ef..11b15b92c 100644
--- a/Source/Additions/NSError+GNUstepBase.m
+++ b/Source/Additions/NSError+GNUstepBase.m
@@ -28,8 +28,8 @@
  */
 #ifdef	_XOPEN_SOURCE
 #undef	_XOPEN_SOURCE
-#define	_XOPEN_SOURCE 600
 #endif
+#define	_XOPEN_SOURCE 600
 
 #import "common.h"