editor/xemacs21 update to 21.4.15

[Gregory Steuck <greg_(_at_)_y2004_(_dot_)_nest_(_dot_)_cx>]

Hello,

There is an update for xemacs21 to 21.4.15.
http://home.nest.cx:8/greg/editor-xemacs21-up-21.4.15.patch.gz

It also includes some security patches:
* gnuserv does not listen on TCP sockets
* tempname replaced with mkstemp

I only tested the port on 3.5-with-current-ports-infractructure-i386 and
only the standard flavor.

Thanks
Greg