Licensing

I may have some spare hacking time coming up, and I was thinking about
adding a PL (Scheme) to PostgreSQL.  I've found some code out there
for a small Scheme interpreter, but it appears to be licensed under a
"BSD with advertising clause" license (as opposed to the "modern BSD"
license of PostgreSQL).  The license text includes:
   Redistributions of source code must retain the above copyright   notice, this list of conditions and the following
disclaimer.
   Redistributions in binary form must reproduce the above copyright   notice, this list of conditions and the
followingdisclaimer in   the documentation and/or other materials provided with the   distribution.
 

Would it be a problem to include this code in PG?  

-Doug
-- 
Let us cross over the river, and rest under the shade of the trees.  --T. J. Jackson, 1863