https://bugs.gentoo.org/869134

From 09844ce4ca3d5975469640cea9c5414d5c0baa44 Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Thu, 8 Sep 2022 04:45:03 +0200
Subject: [PATCH] Fix a warning regarding strncmp.

Reported by Sam James in <https://savannah.gnu.org/bugs/?63031>.

* lib/getopt.c (strncmp): Declare with a prototype.
--- a/lib/getopt.c
+++ b/lib/getopt.c
@@ -194,7 +194,6 @@ static char *posixly_correct;
    whose names are inconsistent.  */
 
 extern char *getenv ();
-extern int strncmp ();
 
 static char *
 my_index (const char *str, int chr)
@@ -209,6 +208,7 @@ my_index (const char *str, int chr)
 }
 
 extern int strcmp (const char *, const char *);
+extern int strncmp (const char *, const char *, size_t);
 extern size_t strlen (const char *);
 
 #endif /* not __GNU_LIBRARY__ */