Use util_getenv(). Honour outfolder variable, when set.

@@ -45,9 +45,6 @@ mail_copy0 (int argc, char **argv, int mark)
   else
     filename = strdup ("mbox");
 
-  if (!filename)
-    return 1;
-  
   if (msgset_parse (argc, argv, &msglist))
     {
       if (filename)
@@ -56,14 +53,13 @@ mail_copy0 (int argc, char **argv, int mark)
     }
 
   if (sender)
-    {
-      filename = util_get_sender(msglist->msg_part[0], 1);
+    filename = util_outfolder_name (util_get_sender (msglist->msg_part[0], 1));
+
   if (!filename)
     {
       msgset_free (msglist);
       return 1;
     }
-    }
 
   if (mailbox_create_default (&mbx, filename)
       || mailbox_open (mbx, MU_STREAM_WRITE | MU_STREAM_CREAT))