+#if __GNUC__ > 1
+#define ATTRIBUTE(X) __attribute__ (X)
+#else
+#define ATTRIBUTE(X)
+#endif
+
+#define UNUSED ATTRIBUTE ((unused))
+#define NO_RETURN ATTRIBUTE ((noreturn))
+#define PRINTF_FORMAT(FMT, FIRST) ATTRIBUTE ((format (printf, FMT, FIRST)))
+#define SCANF_FORMAT(FMT, FIRST) ATTRIBUTE ((format (scanf, FMT, FIRST)))
+
+void panic (const char *, ...)
+ __attribute__ ((format (printf, 1, 2), noreturn));
+void backtrace (void);
+
+#endif /* debug.h */
+
+/* This is outside the header guard so that debug.h may be
+ included multiple times with different settings of NDEBUG. */
+#undef ASSERT
+#undef NOT_REACHED
+