1 files changed, 6 insertions, 4 deletions

diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index ec5f124a366..59f9e6c71d1 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -101,10 +101,12 @@ struct random_data
 
 /* The __attribute__ feature is available in gcc versions 2.5 and later.
    The attribute __pure__ was added in gcc 2.96.  */
-#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
-# define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
-#else
-# define _GL_ATTRIBUTE_PURE /* empty */
+#ifndef _GL_ATTRIBUTE_PURE
+# if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
+#  define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
+# else
+#  define _GL_ATTRIBUTE_PURE /* empty */
+# endif
 #endif
 
 /* The definition of _Noreturn is copied here.  */