# define NONNULL(ARGS)
# define ALWAYSINLINE
# endif
+# if __GNUC__>3
+# define PURE __attribute__((__pure__))
+# else
+# define PURE
+# endif
#else
# define NONNULL(ARGS)
# define UNUSED
# define NORETURN
# define ALWAYSINLINE
+# define PURE
#endif
#if !defined(__STDC_VERSION__) || (__STDC_VERSION__<199901L)