https://bugs.gentoo.org/969521
Patch by Jonathan Lovelace
Bug also happens on gcc-musl system, this fixes it.
diff -ru a/src/getopt.h b/src/getopt.h
--- a/src/getopt.h	2010-01-14 05:45:46.000000000 -0500
+++ b/src/getopt.h	2026-02-02 11:34:49.329689765 -0500
@@ -144,7 +144,6 @@
    errors, only prototype getopt for the GNU C library.  */
 extern int getopt (int __argc, char *const *__argv, const char *__shortopts);
 # else /* not __GNU_LIBRARY__ */
-extern int getopt ();
 # endif /* __GNU_LIBRARY__ */
 
 # ifndef __need_getopt