From http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/net-nds/openldap/files/

Upstream-status: Pending

--

--- a/configure.in
+++ b/configure.in
@@ -1227,7 +1227,7 @@ if test $ol_link_tls = no ; then
 				ol_with_tls=gnutls
 				ol_link_tls=yes
 
-				TLS_LIBS="-lgnutls"
+				TLS_LIBS="-lgnutls -lgcrypt"
 
 				AC_DEFINE(HAVE_GNUTLS, 1, 
 					[define if you have GNUtls])