/* If NULL, error will flush stdout, then print on stderr the program
name, a colon and a space. Otherwise, error will call this
function without parameters instead. */
-void (*error_print_progname) ();
+void (*error_print_progname) (
+#if __STDC__
+ void
+#endif
+ );
/* This variable is incremented each time `error' is called. */
unsigned int error_message_count;