$NetBSD$

--- agrep/checkfile.c.orig	1999-11-03 21:37:06.000000000 +0100
+++ agrep/checkfile.c
@@ -24,7 +24,9 @@
 #define MAXLINE 512
 
 extern char Progname[];
+#ifndef errno
 extern int errno;
+#endif
 
 unsigned char ibuf[MAXLINE];
 
