Custom license question (Glk libraries)

[Niko Tyni <ntyni@iki.fi>]

Hi,

I'm packaging a set of Glk user interface libraries [1], which are
distributed under a custom license, included below. In my limited
understanding this is both DFSG-free and GPL-compatible, but I'd like
to be sure about this. The libraries are going to be linked against
GPL- and BSD-licensed code.

[1] http://www.eblong.com/zarf/glk/

>From the README of the xglk library:

 XGlk: X Windows Implementation of the Glk API.

 XGlk Library: version 0.4.11
 Glk API which this implements: version 0.6.1.
 Designed by Andrew Plotkin <erkyrath@eblong.com>
 http://www.eblong.com/zarf/glk/index.html

 This is source code for an implementation of the Glk library which runs
 under X windows.

 [...]

 * Permissions

 The source code in this package is copyright 1998-9 by Andrew Plotkin. You
 may copy and distribute it freely, by any means and under any conditions,
 as long as the code and documentation is not changed. You may also
 incorporate this code into your own program and distribute that, or modify
 this code and use and distribute the modified version, as long as you retain
 a notice in your program or documentation which mentions my name and the
 URL shown above.


Please CC me on replies, I'm not subscribed to the list.

Thanks,
-- 
Niko Tyni		ntyni@iki.fi