[Samba] 3.0.11 - configure can't see ldap.h

[Mike]

My server is running OpenBSD 3.6.  I wish to join this machine to a 
Windows 2003 AD domain so Windows clients can copy files to and from it 
for FTP use.

I have untar'd the following files to /usr/src:

   openldap-stable-20050125.tgz
   samba-3.0.11.tar.gz

When running configure it stops with this error:

checking for LDAP support... yes
checking ldap.h usability... no
checking ldap.h presence... no
checking for ldap.h... no
checking lber.h usability... no
checking lber.h presence... no
checking for lber.h... no
configure: error: ldap.h is needed for LDAP support

These are my configure options:
./configure \
--with-ldap \
--with-ads \
--includedir=/usr/src/openldap-2.2.23/ \
--with-krb5=/etc/kerberosV

The missing file *is* in the openldap-2.2.23/include folder.  I have 
tried copying the ldap.h file to the samba/source/include folder but 
that doesn't help.  I can't seem to get Samba to see this file.  Sorry 
if this an often asked question.  I searched Google for an hour and 
found other people with this problem but no solution.

--
Regards,

Mike