bzflag license

[Sven LUTHER <luther@maxime.u-strasbg.fr>]

Hello, ...

I am thinking about packaging bzflags (http://groundhog.pair.com/bzflag), and
would want ot know what you think about the license
(http://groundhog.pair.com/bzflag/license.html), it is claimed to be
opensource (as per www.opensource.org) but the following clause seems suspect
to me :

3. Redistribution and use of modified source and binary forms are
   permitted provided that at least one of the following conditions are met:
	
  A. Modifications are placed in the public domain or are
     made available under this license, or permission to use
     the modifications is granted to the Copyright Holder.
	  
  B. Use of the modified version is restricted to within
     the corporation or organization that made the modifications.

  C. Other distribution arrangements are made with the Copyright Holder.

Friendly,

Sven LUTHER