FreeBSD 8.0 i386, plpythonu, threaded Python not supported on this platform

Hi all!

./configure --prefix=$HOME/inst/pg-9 --enable-nls --enable-debug --enable-depend --enable-cassert
--enable-thread-safety--with-pgport=5431 --with-libxml --with-libxslt --with-python --with-perl --with-tcl
FLEX=/usr/local/bin/flex

--8<---------------cut here---------------start------------->8---
checking for python... /usr/local/bin/python
checking for Python distutils module... yes
checking Python configuration directory... /usr/local/lib/python2.6/config
checking how to link an embedded Python application... -L/usr/local/lib/python2.6/config -lpython2.6 -lutil -lm
checking whether Python is compiled with thread support... yes
configure: error: threaded Python not supported on this platform
--8<---------------cut here---------------end--------------->8---

Where can I find a description of this problem? Is any chance to fix it?

-- 
Sergey Burladyan