That's nice. It's also not what I asked. I asked what it was that made it
GPL-incompatible.
6. Redistributions of any form whatsoever must retain the following
acknowledgment:
"This product includes PHP software, freely available from
<http://www.php.net/software/>".
I don't remember why, but this is incompatable with the GPL. IIRC,
it's the difference that makes the modified BSD Licence GPL
Compatable, and the Original BSD Licence Incompatable.
It's a practical problem if there are many such acknowlegment.