+extern int
+errdetail_log(const char *fmt,...)
+/* This extension allows gcc to check the format string for consistency with
+ the supplied arguments. */
+__attribute__((format(printf, 1, 2)));
+
+extern int
+errdetail_plural(const char *fmt_singular, const char *fmt_plural,
+ unsigned long n, ...)
+/* This extension allows gcc to check the format string for consistency with
+ the supplied arguments. */
+__attribute__((format(printf, 1, 4)))
+__attribute__((format(printf, 2, 4)));
+