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

Upstream-Status: Pending

--- a/configure.ac
+++ b/configure.ac
@@ -1263,7 +1263,7 @@ if test $ol_link_tls = no ; then
 				ol_link_tls=yes
 				WITH_TLS_TYPE=gnutls
 
-				TLS_LIBS="-lgnutls"
+				TLS_LIBS="-lgnutls -lgcrypt"
 
 				AC_DEFINE(HAVE_GNUTLS, 1, 
 					[define if you have GNUtls])