+/* GCC lets us add "attributes" to functions, function
+ parameters, etc. to indicate their properties.
+ See the GCC manual for details. */
+#define UNUSED __attribute__ ((unused))
+#define NO_RETURN __attribute__ ((noreturn))
+#define NO_INLINE __attribute__ ((noinline))
+#define PRINTF_FORMAT(FMT, FIRST) __attribute__ ((format (printf, FMT, FIRST)))
+
+/* Prints a debug message along with the source file name, line
+ number, and function name of where it was emitted. CLASS is
+ used to filter out unwanted messages. */
+#define DEBUG(CLASS, ...) \
+ debug_message (__FILE__, __LINE__, __func__, #CLASS, __VA_ARGS__)