Index: generic/nsf.h
===================================================================
diff -u -N -r1fb16685007123a71b3ee8fb69b8ab67214aed82 -r7ad03f0f42ae651084aefb409c6c00b2318821c7
--- generic/nsf.h	(.../nsf.h)	(revision 1fb16685007123a71b3ee8fb69b8ab67214aed82)
+++ generic/nsf.h	(.../nsf.h)	(revision 7ad03f0f42ae651084aefb409c6c00b2318821c7)
@@ -386,7 +386,13 @@
 # define NSF_nonnull_assert(assertion) assert((assertion))
 #endif
 
+#if __GNUC_PREREQ(2, 96)
+# define NSF_pure __attribute__((pure))
+#else
+# define NSF_pure
+#endif
 
+
 /*
  * Unfortunately, we can't combine NSF_attribute_format() with
  * functions called via stubs.