$NetBSD$

Add fnm_extmatch.h include.

--- mksquashfs.c.orig	2014-05-12 18:18:20.000000000 -0400
+++ mksquashfs.c	2016-04-08 11:41:27.000000000 -0400
@@ -76,6 +76,7 @@
 #include "read_fs.h"
 #include "restore.h"
 #include "process_fragments.h"
+#include "fnm_extmatch.h"
 
 int delete = FALSE;
 int fd;
