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

Upstream-status: Unknown

--

--- openldap-2.4.28/configure.in.orig	2012-02-11 22:40:36.004360795 +0000
+++ openldap-2.4.28/configure.in	2012-02-11 22:40:13.410986851 +0000
@@ -1214,7 +1214,7 @@
 				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])