Index: generic/nsf.h
===================================================================
diff -u -r695325563d9a19c086388df3d98e7687246c97f4 -r16a02881bff0a0d626d0045dfd96660338d0c314
--- generic/nsf.h	(.../nsf.h)	(revision 695325563d9a19c086388df3d98e7687246c97f4)
+++ generic/nsf.h	(.../nsf.h)	(revision 16a02881bff0a0d626d0045dfd96660338d0c314)
@@ -361,6 +361,13 @@
 # define NSF_nonnull(ARGS)
 #endif
 
+#if __GNUC_PREREQ(6, 0)
+# define NSF_nonnull_assert(assertion) 
+#else
+# define NSF_nonnull_assert(assertion) assert((assertion))
+#endif
+
+
 /* unforunately, we can't combine NSF_attribute_format() with functions called via stubs */
 #if __GNUC_PREREQ(3, 4)
 # define NSF_attribute_format(ARGS) __attribute__((format ARGS))