$NetBSD: patch-ad,v 1.2 2019/10/12 21:14:22 rillig Exp $

Fix build with GCC 4.

--- src/mergeunit.hxx.orig	1998-05-12 16:49:13.000000000 +0000
+++ src/mergeunit.hxx	2007-12-01 16:40:09.000000000 +0000
@@ -49,6 +49,7 @@ Author:		Jim Fullton, MCNC/CNIDR
 
 #include "defs.hxx"
 #include "idbobj.hxx"
+#include "filemap.hxx"
 
 #define LIM 10000