Explicitly set visibility for external API functions, idea from Marc Provost.

--HG--
branch : HEAD
diff --git a/lib/zip_get_archive_comment.c b/lib/zip_get_archive_comment.c
index 67efd99..c8d38aa 100644
--- a/lib/zip_get_archive_comment.c
+++ b/lib/zip_get_archive_comment.c
@@ -1,8 +1,6 @@
 /*
-  $NiH: zip_get_archive_comment.c,v 1.4 2006/04/23 16:11:33 wiz Exp $
-
   zip_get_archive_comment.c -- get archive comment
-  Copyright (C) 2006 Dieter Baron and Thomas Klausner
+  Copyright (C) 2006-2007 Dieter Baron and Thomas Klausner
 
   This file is part of libzip, a library to manipulate ZIP archives.
   The authors can be contacted at <nih@giga.or.at>
@@ -35,12 +33,11 @@
 
 
 
-#include "zip.h"
 #include "zipint.h"
 
 
 
-const char *
+ZIP_EXTERN const char *
 zip_get_archive_comment(struct zip *za, int *lenp, int flags)
 {
     if ((flags & ZIP_FL_UNCHANGED)