compiling samba on RH 7.3 --with-ldapsam

could anybody help me out on this thing? I 'm trying to compile samba 
with ldapsupport. .Configure ends with no errors except that stat_tls is 
  not included while the howto says it should.
MAKE however returns an error when linking SMBD:

Error message:

"/usr/bin/ld: cannot find -lldap"

Could someone tell what to make of this?

Thanks in advance.

regards,

rob