+/*
+ * Let callers be aware of the constant return value; this can help
+ * gcc with -Wuninitialized analysis. We restrict this trick to gcc, though,
+ * because some compilers may not support variadic macros. Since we're only
+ * trying to help gcc, anyway, it's OK; other compilers will fall back to
+ * using the function as usual.
+ */
+#ifdef __GNUC__
+#define error(...) (error(__VA_ARGS__), -1)
+#endif
+