$NetBSD: patch-ab,v 1.3 2011/09/18 16:51:32 ryoon Exp $

Generalise for all *BSD (well, anything with Torek stdio, really)

--- rxfn.c.orig	2000-11-01 18:04:28.000000000 +0000
+++ rxfn.c
@@ -40,8 +40,10 @@
 #ifndef _CNT
 # ifdef linux
 #  define _CNT(fp) ((fp)->_IO_read_end - (fp)->_IO_read_ptr)
+# elif defined(__DragonFly__)
+#   define _CNT(fp) (((struct __FILE_public *)fp)->_r)
 # else
-#  ifdef __FreeBSD__
+#  if (defined(BSD) && BSD >= 199306)
 #   define _CNT(fp) ((fp)->_r)
 #  else
 #   define _CNT(fp) ((fp)->_cnt)