$NetBSD$

--- index/build_in.c.orig	2002-10-11 07:28:32.000000000 +0200
+++ index/build_in.c
@@ -605,7 +605,9 @@ traverse1()
     int ret;
     char s[MAX_LINE_LEN], es1[MAX_LINE_LEN], es2[MAX_LINE_LEN], es3[MAX_LINE_LEN];
     char s1[MAX_LINE_LEN];
+#ifndef errno
     extern int errno;
+#endif
     static int maxsortlinelen = 0;
     int	i;
 
