I tried you're suggestion, going from 2.4.11 to 2.4.16 and now, when I run make, I get the following:
What SSL implementation are you trying to use? I believe Solaris ships with an older, unsupported release of GnuTLS, so you need to either build (or install) your own version of OpenSSL or a newer release of GnuTLS, and then point slapd at its headers & libraries.
--Quanah -- Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration