--- srfi-14.c	2008-05-04 14:39:48.000000000 -0700
+++ srfi-14.c	2008-11-20 21:00:49.453125000 -0800
@@ -21,8 +21,9 @@
 #  include <config.h>
 #endif
 
-
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE  /* Ask for `isblank ()'.  */
+#endif
 
 #include <string.h>
 #include <ctype.h>