$OpenBSD: patch-agrep_agrep_h,v 1.1 2016/03/18 16:41:53 naddy Exp $
--- agrep/agrep.h.orig	Thu Nov 21 03:28:42 1996
+++ agrep/agrep.h	Thu Mar 17 23:31:02 2016
@@ -11,6 +11,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <string.h>
+#include <errno.h>
 
 #define MAXNUM_PAT  16	/* 32 parts of a pattern = width of expression-tree */
 #define CHAR	unsigned char
