+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
+#define ALLOC_SIZE(...) __attribute__((alloc_size(__VA_ARGS__)))
+#define CHECK_PRINTF(fmt, arg) __attribute__((format(printf, fmt, arg)))
+#else
+#define ALLOC_SIZE(...)
+#define CHECK_PRINTF(fmt, arg)
+#endif
+
+/* Silence the compiler's "unused variable" warning. */
+#define NMH_UNUSED(i) (void)i
+