Fix build with GCC 15
https://bugs.gentoo.org/945196

--- a/src/report.c
+++ b/src/report.c
@@ -253,8 +253,6 @@ get_errmsg()
 {
 /*	Return pointer to static string which gives full filesystem error message.
 */
-	extern int errno;
-	extern char *strerror();
 
 	return strerror(errno);
 }