Milter-greylist

I have been unable to compile milter-greylist on debian with anything
but the basic features:

$ ./configure --with-user=smmsp --enable-dnsrbl
--with-dumpfile=/usr/lib/milter-greylist

..

checking for pthread_create in -lpthread... no
checking for pthread_create in -lc_r... no
checking for pthread_create in -lpthreads -lpthread... no
Required libpthread not found. Use --with-libpthread

If I use --with-libpthread=/lib, I get the same result.

I can successfully run the ./configure command with no arguments.

I can confirm that libpthread exists:

$ ls -l /lib |grep  pthread
-rw-r--r--  1 root root   81701 2007-02-22 02:13 libpthread-0.10.so
lrwxrwxrwx  1 root root      18 2007-04-22 06:40 libpthread.so.0 ->
libpthread-0.10.so

I have had this problem with 3.1.8 and 4.0

Can anybody help?