https://bugs.gentoo.org/944985

--- a/src/error.c
+++ b/src/error.c
@@ -56,7 +56,6 @@ void exit ();
 extern char *program_name;
 
 #ifdef HAVE_STRERROR
-char *strerror ();
 #else
 extern char *sys_errlist[];
 extern int sys_nerr;