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

--HG--
branch : HEAD
diff --git a/lib/zip_set_archive_comment.c b/lib/zip_set_archive_comment.c
index 86bb991..a2286e8 100644
--- a/lib/zip_set_archive_comment.c
+++ b/lib/zip_set_archive_comment.c
@@ -1,8 +1,6 @@
 /*
-  $NiH: zip_set_archive_comment.c,v 1.2 2006/04/23 15:26:30 dillo Exp $
-
   zip_set_archive_comment.c -- set 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>
@@ -37,12 +35,11 @@
 
 #include <stdlib.h>
 
-#include "zip.h"
 #include "zipint.h"
 
 
 
-int
+ZIP_EXTERN int
 zip_set_archive_comment(struct zip *za, const char *comment, int len)
 {
     char *tmpcom;