Licence compatibility for James Clark's XT

Hello,

I'm working on a project that may need a Java XSL processor some way 
down the line. We intend to release the project under GPL and I'm 
doing research on what's available to work with.

I have been in touch with the GNU ClasspathX mailing list and it was 
suggested I ask you about the status of James Clark's XT, now 
maintained by Bill Lindsey.

http://www.blnz.com/xt/xt-20020426a-src/index.html

See the two links near the top of the page.

To me, the permission seems open and free, but I would appreciate a 
more authoritative opinion.

Best regards,

Phil